Hutchison's 

Physiology 

and Hygien 






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TREATISE 



Physiology and Hygiene 



FOR 



EDUCATIONAL INSTITUTIONS AJSD GENEEAL 
EEADEES. 



FULLY ILLUSTRATED. 





BY 

Joseph C. Hutchison, M.D., L.L.D., 

EX-PRESIDENT OF THE NEW YORK PATHOLOGICAL SOCIETY, EX-VICE PRESIDENT OF THE 

NEW YORK ACADEMY OF MEDICINE, SURGEON TO THE BROOKLYN CITY 

HOSPITAL, LATE PRESIDENT OF THE MEDICAL SOCIETY 

OF THE STATE OF NEW YORK, ETC., ETC. 



NEW YORK: 

Clark & Maynard, Publishers, 

771 Broadway and 67 & 69 Ninth St. 

1887. 






A COMPLETE COURSE 

IN 

PHYSIOLOGY AND HYGIENE. 

BY 

JOSEPH C. HUTCHISON, M.D., LL.D., 

Ex-President of the New York Pathological Society; Vice-President of the 

New York Academy of Medicine; Surgeon to the Brooklyn City 

Hospital; late President of the Medical Society of the 

State of New York. 

Fikst Lessons in Physiology and Hygiene- 
A Book for Elementary Grades. 160 Pages, 16mo, Cloth. 

The Laws of Health. 
Intended for Grammar Grades. 223 Pages, 16mo, Cloth. 

Physiology and Hygiene. 
A Work for High Schools and Academies. 320 Pages, 12mo, Cloth. 

Each book in the course complies with the laws requiring instruc- 
tion in the physiological effects of stimulants and narcotics. 

Copyright, 1884, by Clark & Maynard. 

Gift r . - 
e and Mrs. fsaac R. Hltt 
v»uly 3, 1933 



TO MY WIFE 



WHOSE SYMPATHY HAS, FOR MOKE THAN TWENTY YEARS, LIGHTENED THE CARES 

INCIDENT TO 



AN ACTIVE PROFESSIONAL LIFE, 



THIS HUMBLE VOLUME 



IS AFFECTIONATELY INSCRIBED. 



PREFACE, 



THIS work is designed to present - , the leading facts and principles 
of human Physiology and Hygiene in clear and concise language, 
so that pupils in schools and colleges, and readers not familiar with 
the subjects, may readily comprehend them. Anatomy, or a descrip- 
tion of the structure of an organ, is of course necessary to the under- 
standing of its Physiology, or its uses. Enough of the former study 
has, therefore, been introduced to enable the pupil to enter intelli- 
gently upon the latter. 

Familiar language, as far as practicable, has been employed, rather 
than that of a technical character. "With a view, however, to 
supply what might seem to some a deficiency in this regard, a 
Pronouncing Glossary has been added, which will enable the in- 
quirer to understand the meaning of many scientific terms not in 
common use. 

In the preparation of the work the writer has carefully examined 
all the best material at his command, and freely used it ; the special 
object being to have it abreast of the present knowledge on the sub- 
jects treated, as far as such is possible in a work so elementary as 
this. The discussion of disputed points has been avoided, it being 
manifestly inappropriate in a work of this kind. 

Instruction in the rudiments of Physiology in schools does not 
necessitate the general practice of dissection, or of experiments upon 
animals. The most important subjects may be illustrated by draw- 
ings, such as are contained in this work. Models, especially those 
constructed by Auzoux of Paris, dried preparations of the human 
body, and the organs of the lower animals, may also be used with 
advantage. 



4 PREFACE. 

The writer desires to acknowledge his indebtedness to R. M. 
Wyckoff, M.D., for valuable aid in the preparation of the manu- 
script for the press ; and to R. Cresson Stiles, M.D., a skillful 
microscopist and physician, for the chapter " On the Use of the 
Microscope in the Study of Physiology." 



PREFACE TO THE REVISED EDITION. 

In the preparation of this edition, each paragraph has been care- 
fully revised, but the changes that have been made relate chiefly to 
verbal alterations and errors of typography. Several new illustra- 
tions have, however, been introduced, and wherever practicable, the 
names of the organs have been printed on them, instead of under 
them with letters and lines pointing them out. This arrangement 
the pupil will find to be a great improvement. Considerable new 
material has also been added on the influence of alcohol and nar- 
cotics on health. 

The favor with which the book has been received is the most 
conclusive evidence of its adaptation to the needs of the pupiL 



CONTENTS. 



CHAPTER t 



THE FRAMEWORK OP THE BODY. 

The Bones — TJieirform and composition — The Properties of Bone — 
The Skeleton — The Joints — The Spinal Column — The Growth of 
Bone — The Bepoyir of Bone — Changes in the Skeleton — Erect 
Position 15 

CHAPTER IL 

THE MUSCLES. 

The Muscles — Flexion and Extension — The Tendons — Contraction — 
Physical Strength — Necessity for Exercise — Its Effects — Forms of 
Exercise — Walking — Riding — Gymnastics — Open-air Exercise — 
Excessive Exercise — Sleep — Recreation 3X 

CHAPTER IIL 

THT INTEGUMENT, OR SKIN. 

The Integument — Its Structure — The Nails and Hair — The Complex- 
ion — The Sebaceoum Glands— The Perspiratory Glands — Perspi- 
ration and its uses — Importance of Bathing — Different kinds of 
Baths — Manner of Bathing — The Benefits of the Sun- -Impor- 
tance of Warm Clothing — Poisonous Cosmetics 48 

CHAPTER IV. 

THE CHEMISTRY OP FOOD. 

The Source of Food- -Inorganic Substances — Water— Salt — Lime — 
Iron — Organic Substances— Albumen, Fibi«in, and Caseine — The 
Fats or Oils — The Sugars, Starch, and Gum — Stimulating Sub- 
stances — Necessity of a Regulated Diet 65 



CONTENTS, 



CHAPTER V. 

t>AGE 
POOD AND DRINK. 

Necessity for Food — Waste and Repair — Hunger and Thirst — Amount 
of Food — Renovation of the Body — Mixed Diet — Milk — Eggs — 
Meat — Cooking — Vegetable Food — Bread — The Botato — Fruits — 
Burity of Water — Action of Water upon Lead— Coffee, Tea, and 
Chocolate — Effects of Alcohol 81 

CHAPTER VL 

DIGESTION. 

The Brincipal Brocesses of Nutrition — The General Blan of Dige* 
tion — Mastication — The Teeth — Breservation of the Teeth — Insali- 
vation — The Stomach and the Gastric Juice — The Movements of 
the Stomach — Gastric Digestion — The Intestines — The Bile and 
Bancreatic Juice — Intestinal Digestion — Absorption by means of 
Blood-vessels and Lacteals — The Lymphatic or Absorbent System 
— The Lymph — Conditions which affect Digestion — The Quality, 
Quantity, and Temperature of the Food — The Influence of Exer- 
cise and Sleep — The Kidneys — The Spleen — Effect of Alcohol 
upon Digestion, tJie Liver, and Kidneys 104 

CHAPTER VH. 

THE CIRCULATION. 

The Blood — Its Blasma and Corpuscles— CoaguV' ion of the Blood — 
The Uses of the Blood — Transfusion — C7>nge of Color — The 
Organs of the Circulation — The Heart, Ar,<ries, and Veins — The 
Cavities and Valves of the Heart — Its Vital Energy — Bassage of 
tlie Blood through the Heart — The Frequency and Activity of its 
Movements — The Bulse — The Sphygmograph — The Capillary 
Blood-vessels — The Bate of the Circulation — Assimilation — Inju- 
ries to the Blood-vessels — Effects of Alcohol upon the Heart — As a 
Fat-Broducer 129 

CHAPTER VHL 

RESPIRATION. 

The Objects of Respiration — The Lungs— The Air-Bassages — The 
Movements of Respiration — Expiration and Inspiration — The 
Frequency of Respiration — Capacity of the Lungs — The Air we 
Breathe — Changes in the Air from Respiration — Changes in th# 



CONTENTS. 7 

PAGE 

Blood — Interchange of Gases in the Lungs— Comparison between 
Arterial and Venous Blood — Respiratory Labor — Impurities of 
the Air — Dust — Carbonic Acid — Effects of Impure Air — Nature's 
Provision for Purifying the Air — Ventilation — Animal Heat. . . . 154 

CHAPTER IX. 

THE NERVOUS SYSTEM. 

Animal and Vegetative Functions — Sensation, Motion, and Volition— 
The Structure of the Nervous System — The White and Or ay Sub- 
stances—The Brain — Its Convolutions — The Cerebellum — The Spi- 
nal Cord and its System of Nerves — The Anterior and Posterior 
Roots — The Sympathetic System of Nerves — The Properties of Nerv- 
ous Tissue — Excitability of Nervous Tissues — The Functions of the 
Spinal Nerves and Cord — The Direction of the Fibres of the Cord — 
Reflex Activity and its Uses— The Functions of the Medulla Oblon- 
gata and the Cranial Ganglia — The Reflex Action of the Brain 
— Effects of Alcohol, Tobacco, Snuff, Narcotics, Opium, Chloral, 
Hasheesh, Chloroform 181 

CHAPTER X. 

THE SPECIAL SENSES. 

The Production of Sensations — Variety of Sensations — General Sensi- 
bility — Pain and its Function — Special Sensation, Touch, Taste, 
Smell, Sight, and Hearing — The Hand, the Organ of Touch — The 
Sense of Touch — Delicacy of Touch — Sensation of Temperature 
and Weight — The Tongue the Organ of Taste — The Nerves of 
Taste — The Sense of Taste, and its Relations with the other Senses 
— The Influence of Education on the Taste — The Nasal Cavities, 
or the Organs of Smell— The Olfactory Nerve — The Uses of the 
Sense of Smell — The Sense of Sight — Light — The Optic Nerve — 
The Eyeball and its Coverings — The Function of the Iris — The 
Sclerotic, Choroid, and Retina — The Tears and their Function — 
The Movements of the Eyeball — I 1 he Function of Accommodation 
— The Sense of Hearing and Sound — The Ear, or the Organ of 
Hearing— The External, Middle, and Internal Ear 220 

CHAPTER XI. 

THE VOICE. 

Voice and Speech— The Larynx, or the Organ of the Voice— The 
Vocal Cords — The Laryngoscope— The Production of the Voice — 
The Use of the Tongue — The Different Varieties of Voice — The 
Change of Voice — Its Compass— Purity of Tone— Ventriloquy... . 271 



8 CONTENTS. 

CHAPTER m 

THE USE OF THE MICROSCOPE IN THE STUDY OP PHYSIOLOGY. 

The Law of Tissues — Necessity of the Microscope — Different kinds of 
Microscopes — Additional Apparatus — Preliminary Studies — The 
Study of Human Tissues — Tissues of the Inferior Animals — In- 
centives to Study 282 

APPENDIX. 

Poisons and their antidotes 290 

Drowning :... 293 

Care of the Sick-room 293 

Disinfection 295 

Emergencies 297 

Home and Health 300 

On Going into the Country 302 

Glossary 304 



LIST OF ILLUSTRATIONS. 



Frontispiece. 
Viscera in Position. 

1. Section of bone, 

2. The skeleton, .... 

3. Structure of bone, magnified, 

4. Ribs in natural and healthy state, 

5. Eibs showing effects of tight lacing, 

6. Cells of cartilage, 

7. Elbow-joint, .... 

8. Spinal column, 

9. The muscles, .... 

10. Muscular tissue, magnified, . 

1 1. Biceps muscle of the arm, 

12. Muscles and tendons of the hand, 

13. Lower portion of the leg, 

14. Yiew of knee-joint, ..... 

15. Appliance for strengthening the muscles, . 

16. Appliance for strengthening the muscles, 

17. Eoot and transverse section of hair, magnified, 

18. Section of skin, ...... 

19. Granules of potato starch, 

20. Section of the trunk, ..... 

21. Section of a tooth, ..... 

22. Section of the jaws, 

23. Section of the jaws — right side, 

24. Structure of a salivary gland, 

25. Head of a horse, showing salivary gland, etc., 

26. Section of chest and abdomen, 

27. Alimentary canal, . . . 

28. The lacteals, 

29. The kidneys and bladder, 

30. Blood corpuscles, highly magnified, 

31. Blood corpuscles of man and lower animals, magnified, 

32. Circulation of the blood, ) ^ ., 

nn ' > Opposite . 

33. External view of the heart, J 



PAGE 

17 

18 

19 

20 

20 

21 

22 

23 

30 

31 

32 

33 

34 

35 

43 

43 

50 

52 

76 

105 

106 

107 

108 

110 

111 

114 

115 

120 

124 

130 

131 

137 



LIST OF ILLUSTRATIONS. 



l j Opposite . 



10 

no. 

34. Section of the heart, 

35. Left section of the heart 

36. Eight section of the heart 

37. Form of the pulse, 

38. Valves of the veins, .... 

39. Web of frog's foot, magnified, . 

40. Circulation in a frog's foot, . . . 

41. Organs of the chest, .... 

42. Larynx, trachea, and bronchial tubes, . 

43. Diagram of the structure of the air-cells, . 

44. Section of the lungs, .... 

45. Section of mouth and throat, 

46. Ciliated cells, 

47. Ventilation by window, .... 

48. Cerebro-spinal system, .... 

49. Upper surface of the cerebrum, . 

50. Vertical section of the brain, 

51. Base of the brain, ..... 

52. Brain and spinal cord, .... 

53. Section of spinal cord, .... 

54. Sense of touch, 

55. Section of nasal cavity, .... 

56. Front view of the eye, 

57. Vertical section of the eye, magnified, 

58. Front section of eyeball, 

59. Diagram of blind point of the eye, 

60. The retinal image, .... 

61. The different shapes of the globe of the eye, 

62. The function of accommodation, . 

63. The ear and its different parts, . 

64. Showing the internal mechanism of the ear, magnified 

65. Section of the right ear, 

66. Section of the larynx and trachea, 

67. A view of the vocal cords by means of the laryngoscope, 

68. The different positions of the vocal cords, 

69. Double convex and plano-convex lenses 

70. Simple microscope, . 

71. Compound microscope, 



INTRODUCTION. 



rjIHE Human Body is the abode of an immortal spirit, and is the 
-*■ most complete and perfect specimen of the Creator's handiwork. 
To examine its structure, to ascertain the uses and modes of action 
of its various parts, how to protect it from injury, and maintain it in 
a healthy condition, is the design of this work. 

The departments of knowledge which are concerned in these 
investigations, are the science of Human Physiology and the art 
of Hygiene. 

Physiology treats of the vital actions and uses of the various 
parts of living bodies, whether vegetable or animal. Each living 
thing, therefore, has a Physiology. We have a Vegetable Physi- 
ology, which relates to plants ; and an Animal Physiology, relating 
to the animal kingdom. The latter is also divided into Comparative 
Physiology, which treats of the inferior races of animals, and 
Human Physiology, which teaches the uses of the various parts of 
the human body. 

Hygiene, or the art of preserving health, is the practical use of 
Physiology. It teaches us how to cultivate our bodily and mental 
powers, so as to increase our strength, and to fit us for a higher 
enjoyment of life. It also shows us how to prevent some of the 
accidents which may befall the body, and to avoid disease. It is 



12 INTRODUCTION. 

proper that we should understand the construction and power of our 
bodies ; but it is our duty, as rational beings, to know the laws 
by which health and strength may be maintained and disease 
warded off. 

There are various means by which we gain important information 
respecting the Physiology of man. Plants aid us in understanding 
the minute structure of the human body, its circulation, and 
absorption. From inferior animals we learn much in respect to the 
workings of the different organs, as we call those parts of the system 
which have a particular duty to perform. In one of them, as in the 
foot of the frog, we can study the circulation of the blood; in an- 
other, we can study the action of the brain. 

By vivisection, or the laying bare of some organ of a living animal, 
we are able to investigate certain vital processes which are too deeply 
hidden in the human body to be studied directly. This is not necessa- 
rily a cruel procedure, as we can, by the use of anaesthetics, so blunt 
the sensibility of the animal under operation, that he need not suffer 
while the experiment is being performed. There are other means 
by which we gj#Ler our information. There are occasionally men, 
who, from some accident, present certain parts, naturally out of 
view, in exposed positions. In these cases, our knowledge is of 
much greater value than when obtained from creatures lower in the 
scale of being than man. 

We are greatly aided, also, by the use of various instruments of 
modern invention. Chief among these is the microscope, which is, 
as we shall learn hereafter, an arrangement and combination of 
lenses in such a way as greatly to magnify the objects we wish to 
examine. 

We have much to say of Life, or vital activity, in the course of 
our study of Physiology ; but the most that we know of it is seen 
in its results. What Life is, or where its precise position is, we are 
not able to determine. We discover one thing, however, that all 



INTRODUCTION. 13 

the parts of the body are united together with wonderful sympathy, 
so that one part cannot be injured and other parts not suffer damage. 
It is further evident that all organs are not equally important in 
carrying on the work of Life; for some may temporarily suspend 
their action, without serious results to the system, while others must 
never cease from acting. Yet there is nothing superfluous or with- 
out aim in our frames, and no part or organ can suffer harm without 
actual loss to the general bodily health. On this point Science and 
Holy Writ strictly agree. 



PHYSIOLOGY AND HYGIENE. 



CHAPTER I. 

The Framework op the Body. 



The Bones — Their Form and Composition — The Properties of Bone — The 
Skeleton — The Joints — The Spinal Column — The Growth of Bone — The 
Repair of Bone — Changes in the Skeleton — Erect Posture. 

1. The Bones. — The framework which sustains the human body- 
is composed of the Bones. The superstructure consists of the 
various organs on which the processes of life depend. These or- 
gans are soft and delicately formed, and, if unprotected, would, in 
most cases, rapidly be destroyed when subjected to violence, how- 
ever slight. The bones, having great strength and power of resist- 
ance, afford the protection required. {Read Note i. ) 

2. The more delicate the organ, the more completely does Nature 
shield it. For example : the brain, which is soft in structure, is 

1. Self-Knowledge. — " It has been said with truth that the human mind, 
which can survey the heavens and calculate the motion and density of the 
stars, finds itself confounded when, returning from these distant journeyings, 
it enters its own dwelling-place — the body. Man's own organization is still 
among those mysteries of nature which he is least able to penetrate, in spite 
of his incessant efforts to lift the veil which hides it. In all ages he has sought 
to know himself In all times he has studied the relations between his own 
existence and that of the world, and those universal influences which, though 
evident to him, are nearly all inexplicable in their action upon living beings. " 
— Le Pileur on the Human Body. 



1. The framework of the body ? The superstructure ? Softness and delicacy of the 
organs ? How protected ? 

2. The more delicate the organ? Example in relation to the brain? The eye? The 
lungs ? The services performed by the bones ? 



16 THE FRAMEWORK OF THE BODY. 

enclosed on all sides by a spherical box of bone ; the eye, though, it 
must be near the surface of the body to command an extensive 
view, is sheltered from injury within a deep recess of bone ; the 
lungs, requiring freedom of motion as well as protection, are sur- 
rounded by a large " chest " of bone and muscle. The bones serve 
other useful purposes. They give permanence of form to the body, 
by holding the softer parts in their proper places. They assist in 
movement, by affording points of attachment to those organs which 
have power of motion — the muscles. 

3. The Form and Composition of the Bones. — The shape 
and size of the bones vary greatly in different parts of the body, 
but generally they are arranged in pairs, one for each side of the 
body. They are composed of both mineral and animal substances, 
united in the proportion of two parts of the former to one of the 
latter; and we may separate each of these substances from the 
other for examination. First, if we expose a bone to the action of 
fire, the animal substance is driven off, or "burned out." We now 
find that, though the shape of the bone is perfectly retained, what 
is left is no longer tough, and does not sustain weight as before. 
Again, we may remove the mineral portion, which is a form 
of lime, by placing a bone into a dilute acid. The lime will 
be dissolved out, and the shape of the bone remain as before ; 
but now its firmness has disappeared, and it may be bent without 
breaking. 

4. If, for any reason, either of these ingredients is disproportion- 
ate in the bone during life, the body is in danger. The mineral 
substance is useful in giving rigidity of form, while the animal sub- 
stance insures toughness and elasticity, so that by their union, we 
are able to withstand greater shocks and heavier falls than would 
be possible with either alone. In youth, the period of greatest 
activity, the animal portion is in excess ; aboDe then does not break 
so readily, but, when broken, unites with great rapidity and 
strength. On the other hand, the bones of old persons are more 
easily broken, and in some cases fail to unite. The mineral matter 

3. Their shape and size? Of what composed ? Possibility of being separated? Effect 
of fire? Of dilute acid ? 

4. Effect of deficiency of ingredient ? Usefulness of the lime ? Of the animal substance ? 
Effect of their union ? Condition, in youth ? Old ags ? 



THE FRAMEWORK OF THE BODY. 



17 



being then in excess, indicates that the period of active exertion is 
drawing to a close. {Read Note 2). 

5. The Structure of the Bones. — If we examine one of the 
long bones, which has been sawed through lengthwise, we observe 




Fig. 1. — Section of Bone.— A. Longitudinal, 
verse Section of Bone. 



Trans- 



that it is admirably fashioned for affording lightness as well as 
strength (Fig. 1). Its exterior is hard and resisting, but it is 
porous at the broad extremities, while through the central portion 



2. Some Properties of Bone. — "The power of bone to resist decay is 
remarkable. Fossil bones deposited in the ground long before the appearance 
of man upon the earth have been found by Cuvier, exhibiting a considerable 
portion of cartilage. The jaw of the Cambridge Mastodon contained over 
forty per cent, of animal matter — enough to make a good glue — and others 
about the same. From this we see that a nutritious soup might be made from 
the bones of animals that lived before the creation of man. The teeth resemble 
bone in their structure, but resist decay longer ; they are brought up by deep- 
sea dredging, when all other parts of the animal have wasted away. The 
bones differ at different ages, and under different social conditions. In the 
disease called 'rickets,' quite common among the ill-fed children of the poor 
in Europe, but somewhat rare in America, there is an inadequate deposit of 
the mineral substance, rendering the bones so flexible that they may be bent 
almost like wax. In females and weak men the bones are light and thin, 
while in a powerful frame they are dense and heavy. Exercise is as necessary 
to the strength of bone as to the strength of muscle ; if a limb be disused, 
from paralysis or long sickness, the bones lose in weight and strength as well 
as the soft parts. Bone is said to be twice as strong as oak, and, to crush a 
cubic inch of it, a pressure equal to 5,000 pounds is requisite." 



5. In what respect admirably fashioned? Its formation? Microscopic examination? 
The inference ? " Line of beauty ? " 



18 



THE FRAMEWORK OF THE BODY. 




Fig. 2.— The Skeleton. 



THE FRAMEWORK OF THE BODY. 



19 




Fig. 3. 



-Structure of Bone 
Enlarged. 



there is a cavity or canal which contains an 
oily substance, called marrow. If a thin 
section of bone be examined under the mi- 
croscope, we discover that it is pierced by 
numerous fine tubes (Fig. 3), about which 
layers of bone-substance are arranged. So 
that, although a bone be as hard as stone 
externally, it is by no means as heavy, by 
reason of its light interior texture. An- 
other element of power is found in the 
curved outline of the bones. The curved 
line is said to be " the line of beauty," as it 
certainly is the line of strength, and is uni- 
formly present in the bones whose position exposes them to accident. 
6. The Skeleton. — The number of bones in the human body 
exceeds two hundred, and when joined together in their proper 
places, they form what is termed the Skeleton (Fig. 2). It embraces 
three important cavities. The first of these, surmounting the frame, 
is a box of bone, called the skull ; below this, is a bony case, or 
"chest;" and lower down is a bony basin, called the pelvis. The 
two latter compose the trunk. The trunk and skull are maintained 
in their proper relations by the " spinal column." Branching from 
the trunk are two sets of limbs : the arms, which are attached to 
the chest by means of the "collar-bone" and "shoulder-blade;" 
and the legs, directly joined to the lower part of the trunk. 
(Read Note 3.) 

3. Two Forms of Skeleton among Animals. — "The solid basis on 
which all the soft organs of the body rest is the skeleton. In the human body 
the skeleton is composed of a number of bones, each of which has a distinct 
name. In the animal kingdom there are two distinct forms of skeletons ; the 
one which is found chiefly in the lower animals is outside, and covers the soft 
parts, and is called an exo-skeleton. Examples of this kind of skeleton are 
seen in crabs, lobsters, insects, and the shells of mollusca, as oysters, mussels, 
and whelks. The shells of these animals are mostly composed of carbonate of 
lime. Fishes possess an internal skeleton ; and all the classes of animals above 
them, as reptiles, birds, and mammals, possess internal or endo-skeletons. " — 
Lankester's Manual of Health. 



6. Number of bones? Skeleton? The skull? Chest? The trunk? The trunk and skult, 
how maintained ? What of the arms ? Legs ? 



20 THE FRAMEWORK OF THE BODY. 

7. The cavities, three of which we have mentioned, are designed 
for the lodgment and protection of the more delicate and perishable 
parts of the system. Thus, the skull, together with the bones of 
the face, shelters the brain and the organs of four senses — sight, 
hearing, smell, and taste. The chest contains the heart, lungs, and 
great blood-vessels, while the lower part of the trunk sustains the 
liver, stomach, and other organs. 





Fig. 4.— Ribs in a Natural anx> Fig. 5.— Ribs Showing the Effects 

Healthy State. of Tight Lacing. 

8. The Joints. — The point of union of two or more bones 
forms a joint or articulation, the connection being made in vari- 
ous ways according to the kind and amount of motion desired. 
The movable joints are connected by strong fibrous bands, called 
ligaments. These ligaments are of a silvery whiteness, and very 
unyielding ; so much so, that when sudden violence is brought to 
bear in the vicinity of a joint, the bone to which a ligament is at- 
tached may be broken, while the ligament itself remains uninjured. 
When this connecting material of the joints is strained or lacerated 
by an accident, a " sprain " is the consequence. An injury of this 
sort may be, and frequently is, quite as serious as the breaking of a 
bone. {Read Note 4. ) 

4. How Joints may be Injured. — "All the joints are liable to disloca- 
tion — that is, being ' put out ' of their place. Owing to the shallowness of 
the cavity at the shoulder, this joint is frequently dislocated ; and this some- 



7. Design of the cavities? Give the examples. 

8. Joint or articulation ? Movable joints, how compacted? The ligaments of the movable 
joints? What is a sprain ? Consequence of a serious sprain ? 



THE FRAMEWORK OP THE BODY. 21 

9. The ligament, then, secures firmness to the joint ; it must also 
have flexibility and smoothness of motion. This is accomplished 
by a beautiful mechanism, the perfection of which is only feebly 
imitated by the most ingenious contrivance of man. The ends of 
the bones are covered by a thin layer of cartilage, which, being 
smooth; and elastic, renders all the movements of the joint very 
easy. In addition to this, there is an arrangement introduced for 
" lubricating " the joint, by means of a deli- 
cate sac containing fluid. This fluid is con- 
stantly supplied in small quantities, but 
only so fast as it is used up in exercise. In 
appearance, it is not unlike the white of 
an egg^ and hence its name synovia, or egg- 
like. 

10. Thus, we observe that two very dif- 
ferent substances enter into the composition 
of a joint. The ligament, very unyielding, 
affords strength, while the cartilage, elastic 
and moist, gives ease and smoothness of 
motion. The amount of motion provided Fl °- 6 --° ELLS OF Cartilage. 
for varies greatly in different joints. In some there is none at all, 
as in the skull, where one bone is dove-tailed into another by what 
are termed sutures. Others have a hinge-like motion, such as 
those of the elbow, wrist, ankle, and knee ; the most complete of 
these being the elbow-joint (Fig. 7). Belonging to another class, 

times happens with the thigh, but not so often, as the cup in which the 
emur moves is much deeper. Joints which have been dislocated should atf 
once be ' set ' ; but now that you have seen how liable you are to accident, 
I hope you will be careful not to indulge in too violent or rough exercise, by 
which you might not only dislocate the joints, and so in time weaken them, 
but might also break the bones, and perhaps become crippled for life. Many 
children have the habit of pulling their fingers so as to make them ' crack. 
This is exceedingly wrong, for it is to a certain extent pulling the joints out 
of their sockets, and this may so loosen the parts as to cause permanent in- 
jury." — Davidson's " Our Bodies." 




9. Office of the ligament? What must it have? How accomplished? Describe it. 
Synovia ? 

10. What do we observe as regards tbe composition of a joint? Tbe ligament and carti- 
lage ? ' What varies ? Example of the skull ? Other examples ? The ball-and-socket joint ? 



22 



THE FRAMEWORK OF THE BODY. 



the ball-and-socket joint, is that at the shoulder, possessing a free, 
dom of motion greater than any other in the body. 




Fig. 7. — Elbow-Joint. A, Bone of the arm ; B, C, Bones of the fore-arm. 

11. The Spinal Column. — The spinal column is often spoken of 
as the " back-bone," as if it were a single bone, while, in reality, it 
is composed of a chain of twenty-six small bones, called vertebra. 
The spinal column is a wonderful piece of mechanism. It not only 
connects the important cavities of the body, as has already been 
shown, but also, itself forms a canal, which contains the spinal 
cord. The joints of the vertebrae are remarkable for the thick 
layers of cartilage which separate the adjacent surfaces of bone. 
The amount of motion between any two of these bones is not great ; 
but these little movements, taken together, admit of very consider- 
able flexibility, in several directions, without endangering the sup- 
porting power of the column. 

12. The abundant supply of intervertebral cartilage has another 
important use, namely, it adds greatly to the elasticity of the frame. 
It is due, in part, to this elastic material, and in part to the fre- 
quent curves of the spine, that the brain and other delicate organs 



11. What is the spinal column 1 What does it connect and form? Joints of the verte- 
brae ? Amount of motion ? Result ? 

12. Elasticity of the frame ? Protection of the brain from shocks ? Tallness of persons? 
Effects of reclining ? 



THE FRAMEWORK OF THE BODY. 



23 



are not more frequently injured by the shock of sudden falls or 
missteps. During the day, the constant pressure upon these joints, 
while the body is erect, diminishes the thickness of the cartilages ; 
so that a person is not so tall in the evening as in the morning. 
The effects of this compression pass away 
when the body is in a reclining posture. 
{Read Note $.) 



5. Some Causes of Curvature of the 
Spine. — " Much as horse-riding is valued on ac- 
count of the healthful character of its exercise, 
yet an over-indulgence by young ladies — owing 
to the oblique position in which the female form 
rests in the side-saddle — will cause the spine to 
become curved." To avoid this, it is important 
for young ladies to ride occasionally on the op- 
posite side of the horse. Another frequent cause 
of curvature of the spine is the use of the sewing- 
machine, especially among needy seamstresses, 
whose bread frequently depends on the almost un- 
ceasing labor of their hands and feet, while sitting 
in a constrained position. Soon after croquet be- 
came a favorite amusement among the fashionable 
young ladies of England, it was noticed that the 
bent position assumed during the time the mallet 
is used caused a certain deformity, to which was 
given the name of the ' ' croquet curvature. " The 
use of high heels on boots and shoes of children, 
by throwing the weight of the body too far for- 
ward, on the front of the foot, and destroying the 
natural poise of the body, acts an important part 
in causing the spine to become crooked. By many 
this crooked position is considered to be largely a 
school-room disease, for the reason that children 
often are compelled to sit, and write or study, in a Os Coccygis. 
bent posture ; but there must be other causes for it, Fig. 8.— The Spinal Colttmn. 
since it has been found that it is almost exclusively 

a female deformity. Over eighty-four per cent, of the cases is stated by one 
writer to be among girls. But inasmuch as the majority of these cases begin dur- 
ing the years of schooling — from the ages of six to fourteen — great attention 
should be paid to the position of the body during school hours, and ample oppor- 
tunity should be offered, by a regular system of gymnastics, to counteract all the 
evil influences of the school-room posture. — Heather-Bigg on Deform ities(in j.>art\ 



Sacrum. 



24 THE FRAMEWORK OF THE BODY. 

13. The Growth of Bone. — Bone, like all the other tissues of 
the body, is constantly undergoing change, old material being with- 
drawn, to make room for a fresh supply. This change has been 
shown conclusively by experiments. If an animal be fed with 
madder — a red coloring matter — for a day or two, the bones soon 
become tinged ; then, if the madder be discontinued for a few days, 
the original color returns. If, however, this material be alternately 
given and withheld, at short intervals, the bone will be marked by 
a succession of red and white rings. In very young animals, all 
the bones become colored in a single day ; in older ones, a longer 
time is required. The process of waste and repair, therefore, is 
constantly taking place in this hard substance, and with astonishing 
rapidity. 

14. The Repair of Bone. — Nature's provision for uniting broken 
bones is very complete. At first, blood is poured out around the 
ends of the bone, as a result of the injury. This is gradually ab- 
sorbed, and gives place to a watery fluid, which, thickening from 
day to day, acquires, at the end of about two weeks, the consistency oi 
jelly. This continues to harden, by the deposit of new bone-substance, 
until, usually at the end of five or six weeks, the broken bone may 
be said to be united. It is, however, still fragile, and must be used 
carefully a few weeks longer. The process of hardening continues, 
but months must pass before the union can be said to be complete. 
{Read Note b.) 

6. The Management of a Broken Limb. — "Fractures are usually met 
with when the person is dressed. Therefore, unless there is bleeding, or some- 
thing to call for immediate exposure and examination of the damaged part, do 
not be in a hurry to remove the clothes. If the arm be hurt, extemporize a 
sling from a neck-handkerchief or some other article of dress, and support the 
arm from elbow to wrist, tying the ends of the handkerchief in a knot over the 
coat-collar behind. If the thigh or leg be in pain, fasten the injured limb to 
its fellow by a cravat bandage or two, and take care that they lie side by side, 
and on the same level ; or fasten outside the clothes some temporary support — 
a piece or two of straight stick, with a bandage — and then remove the sufferer 
quietly and carefully to some house near at hand. If medical aid be available, 



13. Change in bone? Example— animal and madder. Rapidity of change in color? 
Waste and repair? 

14. How is a broken bone united? What becomes of the blood caused by the injury? 
What takes its place ? How long does it usually take for a broken bone to unite'; 



the framework: of thf body. 25 

15. Changes in the Skeleton.— Man does not reach his full 
height until he is about twenty-five years old ; and even after that 
age, the bones continue to increase in strength and hardness. Be- 
fore that age they are comparatively soft and flexible, by reason of 
the gelatin they contain. This is especially true in childhood ; and 
it is fortunate that it is so, since that condition is much more favor- 
able to the steady and rapid growth of the bones than if they con- 
tained more of the lime, as is the case in old age, when there is no 
occasion for change in the size or shape of the skeleton. The skull, 
however, is said to increase slightly in size, even in advanced life, 
in those persons in whom the brain is continually employed in 
thought or study. However, this very flexibility of the bones, in 
early life, which favors their steady growth and prevents their 
breaking easily, is sometimes the source of serious deformity. A 
young child may be allowed to stand and walk too early, and, as a 
consequence, the lower limbs become permanently bent inward, in 
the distortion called "knock-knees," or outward, as in "bow-legs." 
For the same reason, a bent position of the spinal column, permitted 
to exist habitually in childhood, may result in a life-long deformity. 

16. The Erect Posture. — Youth is, in a great measure, the 
forming as well as the growing period of the frame. Bad habits of 
posture, early formed, become fixed in later life, and their results — 

send for it without any delay ; and be careful, if in the country, and so at 
some distance from the doctor's house, to forward a clear statement as to the 
apparent nature of the accident, which limb is hurt, and where and how it 
happened. Let this statement, too, be in writing, if possible. It may well 
happen, however, that skilled assistance cannot be had, and in this case the 
patient should be undressed quietly and cautiously. It will be far better to slit 
up the dress on the arm or leg with a pair of scissors than to pull it off; but 
however the covering of the injury may be managed, it must be done very 
slowly and gently, and the limb should be supported so as to prevent jarring 
and shaking to the damaged part. It must be carefully kept, too, in a right 
direction, for otherwise some sharp splinter of bore may penetrate the hitherto 
un wounded skin. " — First Help in Accidents and Sickness. 



15. When does a man get his growth? What changes then take place? What difference 
in the bones of a child and those of a man ? What exceptiou in case of the skull ? Bono tit 
in flexibility of bones ? Cause of knock-knees ? Bow-legs ? 

16. What is the forming period? Effects of bad habits of posture? Directions for 
correct posture ? 



26 THE FRAMEWORK OP THE BODY. 

as seen in contracted chests and round shoulders— are with difficulty 
remedied. Right habits, on the other hand, tend to produce an 
erectness of posture which is favorable, not alone to strength and 
health, but also to grace and ease. The following directions should 
be learned and practiced : hold the head erect with the chin some- 
what near the neck ; expand the chest in front ; throw the shoul- 
ders back, keeping them of the same height on both sides ; maintain 
the natural curves of the spine, as shown in the last figure. Man 
alone, of all the animals, has the power to stand and move in the 
erect posture. 



THE FRAMEWORK OP THE BODY. 27 



QUESTIONS FOR TOPICAL REVIEW. 

PAGE 

1. What useful purposes do the hones serve ? 15, 16 

2. State what you can of the composition of the bones 16 

3. Of the usefulness of lime in the bones 16 

4. Of the usefulness of animal substance in the bones 16 

5. State what you can of the structure of the bones 17 

6. Of the strength belonging to the bones 19 

7. What is meant by the human skeleton ? 19 

8. Give a description of its construction 19 

9. What is meant by a joint in the human frame ? 20 

i0. State what you can of the movable joints 20, 21 

11. What office is performed by the ligaments of the joints ? 21 

12. What by the cartilage at the joints ? 21 

13. What movable joints are there ?. 21, 22 

14. Describe the construction of the spinal column 22 

15. What properties and powers does the spinal column possess ? 22, 23 

16. When is a person taller than at other times ? 23 

17. Give the reason for this 23 

18. What can you state of the growth of bone ? 24 

19. Describe the process by which a broken bone is repaired 24 

20. When does man reach his full height ? 25 

21. What changes in the bones then take place ? 25 

22. Name an exception to the general rule 25 

23. State the advantage and disadvantage in the flexibility of bones 25 

24. What directions are given for the correct position ? 26 



28 



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30 



THE MUSCLES. 




Fio. 9.— The Muscles. 



CH^JPTEJ.R n. 

The Muscles. 

The Muscles — Flexion and Extension — The Tendons — Contraction — Physical 
Strength — Necessity for Exercise — Its Effects — Forms of Exercise — Walking 
— Riding —Gymnastics — Open-air Exercise — Effects of Exercise — Excessive 
Exercise — Sleep — Recreation. 

1. The Muscles. — The great mass of the body external to the 
skeleton is composed of the flesh, or Muscles, which largely de- 
termines its outline and weight. The muscles are the organs of 
motion. Their number is about four hundred, and to each of them 
is assigned a separate and distinct office. They have all been 
studied, one by one, and a name given to each, by the anatomist. 
Each is attached to bones which it is designed to move. A few are 
circular in form, and enclose cavities, the size of which they dimin- 
ish by contraction. 

2. If we examine a piece of flesh, we observe that it is soft, and 
of a deep red color. Its structure appears to be composed of layers 

and bundles of small fibres. 
Let us further examine 
these fibres under the mi- 
croscope. We discover 
that these in turn are 
made up of still finei 
fibres, or ftbrillce, as shown 
in Fig. 10. The fibres are 
beautifully marked by par- 
allel wavy lines, about ten 
Fig. 10.-MUSCULAR Tissue. thousand to an inch, which 

a, 6, Striped muscular fibres ; c, The same more • ,-i nr „ n.„ „„„,« ^£ 

highly magnified. give the fibre its name of 




1. What are the muscles ? Their number ? The design of most of them ? Of a few ? 

2. The structure of flesh ? Its color, etc. ? The composition of the fibres? How marked ? 



32 



THE MUSCLES. 



the striped muscular fibre. All of the voluntary muscles present 

this appearance. 
3. Flexion and Extension. — The muscles are, for the most 

part, so arranged in pairs, or corresponding sets, that when motion 
is produced in one direction by one set, there 
is, opposite to it, another muscle, or group of 
muscles, which brings the limb back to its 
place. When they act alternately, a to-and-fro 
movement results. When a joint is bent, the 
motion is called flexion ; and when it is made 
straight again, it is called extension. When 
both sets act equally, and at the same moment, 
no motion is produced, but the body or limb is 
maintained in a fixed position : this occurs 
when we stand erect. The muscles which pro- 
duce extension are more powerful than those 
opposite to them. 

4. The muscles are also distinguished as the 
voluntary and involuntary muscles, according 
as they are, or are not, under the control of the 
wilL The heart is an example of the involun- 
tary variety. We cannot change its action in 
the least by an effort of the will. When we 
sleep, and the will ceases to act, the heart con- 
tinues to beat without cessation. The volun- 
tary muscles, on the other hand, are such as are 
used only when we wish or will to use them — ■ 

as the muscles of the hand or arm (Figs. 11 and 12). {Read Note 1.) 




Fig. 11. — A, Biceps mus 
cle of the arm ; B, C, 
Its tendons. 



1. The Perfection of the Human Hand. — "Gordy counts thirty-four 
distinct movements of the hand, and if we include the combinations of these 
different movements, we shall reach a much higher number. Properl} 7 speak- 
ing, the hand belongs to man alone, and its form does not permit us to con- 
sider it an organ of locomotion, as is the case with certain animals most closely 
resembling man. Nothing gives a more complete idea of the perfection of the 



3. Arrangement of the muscles ? Their action ? Flexion and extension ? Action of the 
muscles when we stand erect? 

4. Kinds of muscles? The voluntary? Involuntary? The- heart? Give the example. 
The hand? Arm? 



THE MUSCLES. 



33 



5. The Tendons. — Tendons, or sinews, are the extremities of 
muscles, and are firmly fastened upon the bone. They are very 





Fig. 12 shows the muscles and tendons of the hand ; A showing the palm, B the hack of the 
hand. These numerous muscles and tendons form a very complicated piece of mechan- 
ism, and help to give to the hand its marvellous dexterity and flexibility. 

mechanism of the hand than the execution of instrumental music. Examine 
an artist while he plays the violin. His fingers rest upon the strings so as to 
leave them exactly of the length necessary for the tones they are to give. The 
half of a millimetre, more' or less, greatly changes the accuracy of the note ; 
and a chord a millimetre out of place produces a note which even the unprac- 
tised ear can recognize as false. But the fingers fall upon the strings at pre- 
cisely the point required. They run over them, succeeding each other with 
giddy rapidity, following every imaginable combination, and yet the hand 
gliding over the instrument incessantly changes its position. Sometimes a 
single finger produces an isolated note ; sometimes two or three act simulta- 
neously to produce a concord ; while a fourth, striking a string with increasing 
rapidity, produces a trill which rivals the nightingale. Add to all these the 
modifications necessary to swell the sound or let it die away — all, in a word, 
that constitutes musical expression, and it will be admitted that this mechan- 
ism is allied to the wonderful, and that it surpasses the most perfect produc- 
tions of human art." A further idea of the rapidity of the hand's movements 
is given in the playing of a skilful pianist, whose hands, oftenest occupied 
together, produce on an average six to eight notes at a time, or about 640 notes 
in a minute in medium time, and 960 notes in extremely quick time. — The 
Wonders of the Human Body. 



34 



THE MUSCLES. 



strong, and of a silvery whiteness. They may be felt just beneath 
the skin, in certain parts of the body, when the muscles are being 
used, as at the bend of the elbow or knee. The largest tendon of 
the body is that which is. inserted into the heel, called the tendon 
of Achilles, after the hero of the Grecian poet, the fable relating that 
it was at this point that he received his death-wound, no other part of 
his body being vulnerable. (Fig. 13). The muscles in the front part 
of the thigh unite to form a single and very 
powerful tendon, and enclose a small bone 
called the knee-pan, which, acting like a 
pulley, greatly increases their power, and at 
the same time protects the front of the knee- 
joint (Fig. 14). 

6. Muscular Contraction. — The muscles, 
when acted upon by the appropriate stimu- 
lus, contract, or so change their shape, that 
their extremities are brought nearer together. 
The bending of the arm, or of a finger, is 
effected in this manner, by the will ; but the 
will is not the only means of producing this 
effect. Electricity, a sharp blow over a mus- 
cle, and other stimuli, also cause it. Con- 
traction does not always cease with life. In 
man, after death from cholera automatic 
movements of hands and feet have been ob- 
served, lasting not less than an hour. In 
eertain cold-blooded animals, as the turtle, contraction has been 
known to take place for several days after the head has been cut off. 
7. The property which, in muscle, enables these movements to 
take place is called contractility. If we grasp a muscle while in 
exercise (for example, the large muscle in the front of the arm), we 
notice the alternate swelling and decrease of the muscle, as we 
move the forearm to and fro. It was at one time supposed that the 




Fig. 13. 
Lower Portion of the Leg. 



5. What are the tendons or sinews? Their strength? Color? Location? Tendon of 
Achilles ? The fable ? Muscles of the leg ? 

6. Contraction of the muscles ? Bending of the arm or finger? Other agencies? Auto- 
matic movements? In cold-blooded animals ? 

7. Contractility? Give the illustration. What was supposed? What is the case ? 



THE MUSCLES. 



35 



muscle actually increased in volume during contraction. This, 
however, is not the case ; for the muscle, while gaining in thickness, 
loses in length in the same proportion ; and thus the volume re- 
mains the same in action and at rest. 




Fig. 14.— View of Knee-joint. A, Thigh bone ; B, Knee-pan ; C, D, Leg hones. 

8. Contraction is not the permanent, or normal, state of a mus- 
cle. It cannot long remain contracted, but after a time it wearies, 
and is obliged to relax. After a short rest, it can then again con- 
tract. It is for this reason that the heart can beat all through life, 
night and day, by having, as we shall hereafter see, a brief interval 
of rest between successive contractions. For the same reason, it is 
more fatiguing to stand for any great length of time in one position, 
than to be walking for the same period. 

9. Relative Strength of Animals. — The amount of muscular 
power which different animals can exert, has been tested by experi- 
ment. By determining the number of pounds which an animal can 
drag upon a level surface, and afterward comparing that with its 
own weight, we can judge of its muscular force. It is found that 
man is able to drag a little less than his own weight. A draught- 
horse can exert a force equal to about two-thirds of his weight 

8. What further in relation to contraction? Weariness of a muscle? Beating of the 
heart? Standing and walking? 

9. Muscular power of animals? How tested? Man's power? Horse's? The comparison? 



36 THE MUSCLES. 

The horse, therefore, though much heavier than man, is relatively 
not so powerful 

10. Insects are remarkable for their power of carrying objects 
larger and heavier than themselves. Many of them can drag ten, 
and even twenty times their weight. Some of the beetles have 
been known to move bodies more than forty times their own weight. 
So far, therefore, from it being a fact that animals have strength in 
proportion to their weight and bulk, the reverse of that statement 
seems to be the law. 

11. Physical Strength. — The difference in strength, as seen in 
different individuals, is not due to any original difference in their 
muscles. Xature gives essentially the same kind and amount of 
muscles to every healthy person, and the power of one, or the weak- 
ness of another, arises, in great part, from the manner in which 
these organs are used or disused. 

12. Many authors complain of the physical degeneracy of men at 
the present day, as compared with past generations. There is room 
for doubt as to the correctness of this statement. Certain experi- 
ments have recently been made with the metallic armor worn seven 
hundred years ago, by which it is found that any man, of ordinary 
height and muscular development, can carry the armor and wield 
the weapons of an age supposed to be greatly our superior in strength. 
When we consider that in those days only very strong men could 
endure the hardships of soldier-life, it is fair to suppose that our age 
has not so greatly degenerated in respect to physical strength. 

13. Importance of Exercise. — Action is the law of the living 
body. Every organ demands use to preserve it in full vigor, and to 
obtain from it its best services. The value of that training of the 
mind, which we call education, is everywhere recognized. The 
child is early put to school, and for many years continues to study, 
in order that his brain, which is the great centre of mental power, 
may act healthfully and powerfully. It is important that the mus- 
cles, also, should receive their education by exercise. This is true, 

10. Power of insects ? Beetles? Give the conclusion. 

11. Difference in strength of individuals? How caused? 

12. Complaint in relation to degeneracy? How true? How determined by armor ? The 
fair supposition ? 

13. Action ? Use of organs ? Training of the mind ? The child's brain ? Education of 
the body? 



THE MUSCLES. 37 

not only in respect to ^children, but also of adults whose occupation 
confines them within doors, and requires chiefly brain- work. 

14. Persons who are engaged in manual labor in the open air 
obtain all the exercise necessary for bodily health in their regular 
business : their need is more likely to be a discipline or exercise of 
the mind. A perfect business of life, therefore, would be one 
which would combine both physical and mental labor in their 
proper proportions. If such a business were possible for all the 
human race, life would thereby be vastly prolonged. Such, in fact, 
is to a large extent the occupation pertaining to one period of life — 
childhood. One part of the time is given to study, and another 
to muscular education by means of games and sports. The restless- 
ness and playfulness of children is not only natural but beneficial. 

15. The Effects of Exercise. — Exercise consists in a well-regu. 
lated use of the voluntary muscular system. The effects, however, 
are not limited to the parts used. Other organs, which are not 
under the control of the will, are indirectly influenced by it. The 
heart -beats more rapidly, the skin acts more freely, the temperature 
rises, the brain is invigorated, and the appetite and power of diges- 
tion are increased. An increased exhalation from the lungs and 
skin purifies the current of the circulation, and the body as a whole 
thrives under its influence. {Read Note 2. ) 

2. Health in Athletic Exercise.—" Health is perpetual youth— that is, 
a state of positive health. Merely negative health, the mere keeping out of 
the hospital for a number of years, is not health. Health is to feel the body a 
luxury, as every vigorous child does ; as the bird does when it shoots and 
quivers through the air, not flying for the sake of the goal, but for the sake of 
flight ; as the dog does when he scours madly across the meadows, or plunges 
into the muddy blissfulness of the stream ; but neither bird, nor dog, nor 
child enjoys his cup of physical happinsss — let the dull or the worldly say 
what they will — with a felicity so cordial as the educated palate of conscious 
manhood. To 'feel one's life in every limb,' this is the secret bliss of which 
all forms of athletic exercise are merely varying disguises ; and it is absurd to 
say that we cannot possess this when character is mature, but only when it is 
half developed. As the flower is better than the bud, so should the fruit be 
better than the flower." 



14. Work in the open air? A perfect business? The consequence of universal perfect 
business? Occupation of children ? 

15. In what does exercise consist? Effects of it? 



38 THE MUSCLES. 

16. The first effects of exercise, however, are upon the muscles 
themselves; for by use they become rounded out and firm, and increase 
in power. If we examine a muscle thus improved by exercise, we 
find that its fibres have become larger and more closely blended to- 
gether, that its color is of a darker red, and that the supply of 
blood-vessels has increased. Without exercise the muscle appears 
thin, flabby, and pale. On the other hand, excessive exercise, 
without sufficient relaxation, produces in the muscle a condition not 
very different from that which follows disuse. The muscle is worn 
out faster than nature builds it up, and it becomes flabby, pale, and 
weak. 

17. Violent exercise is not beneficial ; and spasmodic efforts to 
increase the muscular strength are not calculated to secure such a 
result. Strength is the result of a gradual growth, and is most 
surely acquired if the exercise be carried to a point short of fatigue, 
and after an adequate interval of rest. To gain the most beneficial 
results, the exercise should be at regular hours and during a regular 
period, the activity and the time varying with the strength of the 
individual, and carefully measured by it. {Read Note 3. ) 

3. The Ill-effects of Over-exertion. — " It should be recollected that 
the action of the muscles has limits, as well as that of every other organ of 
the body. The muscles and the heart may be taxed too severely, and perma- 
nent derangements may be produced by overtaxing the human body. The 
ancient gymnasts among the Greeks are said to have become prematurely old, 
and the clowns (or acrobats) and athletes of our own days suffer from the 
severe strain put upon their muscular systems. " The effects of boat-racing in 
England have been thus described by Dr. Skey, an eminent surgeon : ' ' The 
men look utterly exhausted. Their white and sunken features and pallid lips 
show serious congestion of the heart and lungs, and the air of weakness and 
lassitude makes it a marvel how such great exertion should have been so nobly 
undergone. We have repeatedly seen the after ill-effects — spitting of blood, 
congested lungs, and weakness of the heart from over-distension." "Persons 
should neither walk, run, leap, or play at any game, to the extent of produc- 
ing permanent or painful exhaustion. All exercise should be attended with 
pleasurable feelings ; and when pain is produced by proper exercise, those who 
suffer should rather seek medical advice than persevere in exercise." — Lankes- 
ter's Manual of Health. 

16. General effect upon the muscles? Special effect? Effects of inaction? Of excessive 
exercise ? 

17. Of violent and spasmodic efforts? Strength, how attained? Give the particulars. 



THE MUSCLES. 39 

18. Different Modes of Exercise. — There are very few who 
have not the power to walk. There is required for it no expensive 
apparatus, nor does it demand a period of preliminary training. 
Walking may be called the universal exercise. With certain foreign 
nations, the English especially, it is a very popular exercise, and is 
practised habitually by almost every class of society; by the 
wealthy who have carriages, as well as by those who have none ; by 
women as well as by men. 

19. Running, leaping, and certain other more rapid and violent 
movements, are the forms of exercise that are most enjoyed in 
childhood. For the child, they are not too severe, but they may be 
so prolonged as to become injurious. Instances have been recorded 
where sudden death has resulted after violent playing, from overtax- 
ing the heart : for example, we have the case of a young girl who, 
while skipping the rope, and endeavoring to excel her playmates by 
jumping the greatest number of times, fell dead from rupture of the 
heart: 

20. Carriage-riding is particularly well suited to invalids and 
persons advanced in life. Horseback exercise brings into use a 
greater number of muscles than any other one exercise, and with it 
there is an exhilaration of feeling which refreshes the mind at the 
same time. It is one of the manliest of exercises, but not less 
suitable for women than for men. To be skilful in riding, it should 
be begun in youth. 

21. For those who live near streams or bodies of water, there are 
the delightful recreations of boating, swimming, and skating. Cer- 
tain of these exercises have a practical importance aside from and 
above their use in increasing the physical vigor. This is especially 
•true of boating and swimming, since they are often the means ol 
saving life. Practice in these exercises also teaches self-reliance, 
courage, and presence of mind. Persons who have become proficient 
in these vigorous exercises are generally the ones who, in times of 
danger, are the quickest to act and the most certain to do so with 
judgment. 

18. What may walking be called? What further is said of walking? 

19. What is said of running, and other like movements? What, as related to childhood? 
What instances are alluded to ? Example ? 

20. Carriage-riding? Horseback -riding ? 

21. Boating, swimming, and skating? 



40 THE MUSCLES. 

22. Physical Culture. — That form of exercise which interests 
and excites the mind, will yield the best results ; but to some per- 
sons no kind of exertion whatever is, at first, agreeable. They 
should, nevertheless, make a trial of some exercise, in the expecta- 
tion that, as they become proficient in it, it will become more 
pleasant. In exercise, as many sets of muscles should be employed 
as possible, open-air exercise being the best. Parlor gymnastics, 
and the discipline of the gymnasium are desirable, but they should 
not be the sole reliance for physical cuKure. No in-door exercise, 
however excellent in itself, can fill the place of hearty and vigorous 
activity in the open air. {Read Note 4. ) 

23. Excessive Exercises.— If negbct of exercise is injurious, 
so also is the excess of it. Violent exertions do harm ; they often 
cause undue strain, and even lasting injury to some part of the body. 
For this reason the spirit of rivalry which leads to tests of endur- 
ance and feats of strength should be discouraged. Those trials of 
the muscles, especially, which are supposed to demand " training," 
should not be encouraged. Training, it is true, can produce a re- 
markable muscular development, so that nearly every muscle of the 
limbs is as large and corded as the arm of a blacksmith; but it is 
too often at the expense of some internal, vital organ. Large 
muscles are not a certain index of good health. It was well known 
by the ancients. that athletes of their day were short-lived, notwith- 
standing the perfection of the physical training then employed. 

4. Exercise should be Pleasurable. — " The world seldom attaches 
much value to things which are plain and easily understood. The dervish in 
the Eastern allegory, well aware of this weakness, knew that it would be in 
vain to recommend the sultan, for the cure of his disease, simply to take 
exercise. He knew that mankind in general required to be cheated, gulled, 
cajoled, even into doing that which is to benefit themselves. He did not, 
therefore, tell the sultan, who consulted him, to take exercise, but he said to 
him : ' Here is a ball, which I have stuffed with certain rare, costly, and 
precious medicinal herbs. Your highness must take this bat, and with it bea/ 
about this ball until you perspire very freely. You must do this every day. ' 
His highness did so, and in a short time the exercise of playing at bat and ball 
with the dervish cured his malady. " — First Help. 



22. What kind of exercise yields the best results ? What advice is given ? 

23. Physical culture among the ancients? In Greece? In schools and colleges at the 
present time? Result to the body and mind ' ? 



THE MUSCLES. 41 

When a person overtasks the heart, or, in other words, " gets out of 
breath," he should regard it as a signal to take rest. It is well 
known that both horses and men, after having been brought into 
" condition " for competitive trials, soon lose the advantages of 
their training after the occasion for it has passed. 

24. Gymnastic Exercises fop Schools and Colleges. — In the 
system of education among the ancients, physical culture predom- 
inated. In ancient Greece, physical exercises in schools were pre- 
scribed and regulated by law, and hence these schools were called 
gymnasia. At the present time, on the contrary, this culture is 
almost wholly unknown, as a part of the course of education, 
in our schools, and but to a limited extent in colleges. In a few of 
our schools, however, physical exercises have been introduced, with 
manifest advantage to the students, and they form a part of the 
regular curriculum of exercises, — as much so as the recitations in 
geography, grammar or Greek. The good effect of the experiments, 
as shown in improved scholarship as well as increased bodily vigor, 
in the institutions where the plan has been tried, will, it is hoped, 
lead to its universal adoption. We should then hear less frequently 
of parencs being obliged to withdraw their children from school, be- 
cause they become exhausted or, perchance, have lost their health 
from intense and protracted mental application. 

25. Were gymnastics more common in our educational institu- 
tions we should not so often witness the sad spectacle of young men 
and women leaving our colleges and seminaries, with finished 
educations it may be, but with constitutions so impaired that the 
life which should be devoted to the accomplishment of noble pur- 
poses must be spent in search of health. Spinal curvatures, which, 
according to the experience of physicians, are now extremely 
frequent, especially among women, would give place to the steady 
gait and erect carriage which God designed his human creatures 
should maintain. {Read Notes 5 and 6. ) 

5. Health and Strength are not always Identical. — "Health and 
strength are not synonymous terms. A person may have great strength in his 
limbs, or in certain muscles about the body, but really not have good health. 
It is altogether a mistaken idea to suppose that physical exercises have for 

24. The result of gymnastics in our colleges and other institutions of learning? 

25. Were gymnastics more common? To what are spinal curvatures duo? 



42 THE MUSCLES. 

26. All the exercises necessary for the proper development of the 
body may be obtained from the use of a few simple contrivances, that 
every one can have at home at little cost — less by far than is spent for 
useless toys. Many of these may be made available in the parlor or 
chamber, though all exercises are far more useful in the open air. A 
small portion of the day thus spent will afford agreeable recreation, as 
well as useful exercise. The Indian club, the wand, the ring, and 
the dumb-bells answer ordinary purposes very well. Illustrations are 
here introduced of a few simple contrivances that may be useful for 
general exercises, and are specially suitable for persons with weak 
spines, or with spines that are the subject of lateral curvature. 

their sole object the attainment of strength. There are other tissues and organs 
in the human system besides the muscular ; and the healthy action of the 
lungs and the stomach is far more important than great strength in the arms, 
legs, or the back. It is here, in this general exercise of all the muscles and 
parts of the body, that a well-regulated system of gymnastics has its great ex- 
cellence. It aims to produce just that development of the human system upon 
which good health is permanently based, described by a distinguished writer 
as follows : — ' Health is the uniform and regular performance of all the 
functions of the body, arising from the harmonious action of all its parts,' — a 
physical condition implying that all are sound, well-fitting, and well-matched. 
Some minds do not look far enough into life to see this distinction, or to value 
it if seen ; they fix their eyes longingly upon strength — upon strength now, and 
seemingly care not for the power to work long, to work well, to work successfully 
hereafter, Avhich is health." — Dr. Nathan Allen on Physical Culture. 

6. On Recreation. — "Our whole method of amusements, especially for 
the young, should be reformed. Gas-light should yield to daylight, night 
vapors in heated and close rooms should give way to fresh air under the open 
heavens, and our young people should be brought up to work and play under 
the ministry of that great solar force which is the most benign and god-like 
agent known to men. Ardent spirits and tobacco should be given up, and in 
their stead genial exercise of riding, gymnastics, and the dance, with music and 
all beautiful arts, should be employed to stir the languid powers and soothe 
the troubled affections. The old Greeks taught music and gymnastics as parts 
of education, and Plato, in urging the importance of these, still maintains that 
the soul is superior to the body, and religion is the crown of all true culture. 
Why may not Christian people take as broad a position on higher ground, and 
with a generous and genial culture associate a faith that is no dreamy sentiment 
or ideal abstraction, but the best power of man and the supreme grace of God." 
— Rev. Dr. Osgood on " The Skeleton in Modern Society." 

26. Proper exercise at home ? How obtained ? What as to regularity? 



THE MUSCLES. 



43 



27. One of the simplest appliances for strengthening the muscles 
of the back, designed chiefly to exercise the muscles on either side 




Fig. 15. 



of the spine, consists of two wooden handles attached to india- 
rubber cords, one of which is attached to a hook made fast in the 
ceiling, or in the top of the door-case ; and the other to another 





PlO 16. 



hook fastened in the wall, door-post, or window-casing, about the 
When traction is made with the left hand, 



height of the shoulder. 



44 THE MUSCLES. 

it exercises the muscles on the left side of the spine, while those on 
the opposite side are left almost at rest, owing to the oblique direc- 
tion given to the shoulders when the right hand grasps the 
horizontal cord. 

28. Fig. 15 shows an appliance consisting of two strong elastic 
cords, with handles, secured to a hook in the floor, so arranged that 
the patient has to stoop forward to reach them. On raising the 
body the spinal muscles are powerfully exercised. Fig. 16 shows 
other modes of using the elastic cords for strengthening the spine 
and chest. 

29. Rest. — We cannot always be active : after labor we must 
rest. We obtain this rest partly by suspending all exertion, as in 
sleep, and partly by a change of employment. It is said that Alfred 
the Great recommended that each day should be divided in the fol- 
lowing manner : " Eight hours for work, eight hours for recreation, 
and eight hours for sleep." This division of time is as good as any 
that could now be made, if it be borne in mind that, when the 
work is physical, the time of recreation should be devoted to the 
improvement of the mind; and when mental, we should then 
recreate by means of physical exercise. 

30. During sleep, all voluntary activity ceases, the rapidity of 
the circulation and breathing diminishes, and the temperature of 
the body falls one or two degrees. In consequence, the body 
needs warmer coverings than during the hours of wakefulness. 
During sleep, the body seems wholly at rest, and the mind is also 
inactive, if we except those involuntary mental wanderings which 
we call dreams. Nevertheless a very active and important physical 
process is going on. Nutrition, or the nourishing of the tissues 
now takes place. While the body is in action, the process of pull- 
ing down predominates, but in sleep, that of building up takes 
place more actively. In this way we are refreshed each night, and 
prepared for the work and pleasures of another day. If sleep is 
insufficient, the effects are seen in the lassitude and weakness 
which follow. Wakefulness is very frequently the forerunner of 

29. Need of repose? How do we obtain rest? Alfred the Great? The eight hour divi- 
sion ot time? 

30. Cessation of voluntary activity ? Temperature of the body ? Consequence ? Body 
and mind during sleep? Nutrition ? Describe it. Consequence of insufficient sleep? 



THE MUSCLES. 45 

insanity, especially among those who perform excessive mental 
labor. 

31. All persons do not require the same amount of sleep, but the 
average of men need from seven to nine hours. There are well- 
authenticated cases where individuals have remained without sleep 
for many days without apparent injury. Frederick the Great 
required only five hours of sleep daily, and Bonaparte could pass 
days with only a few hours of rest. But this long-continued absence 
of sleep is attended with danger. After loss of sleep for a long 
period, in some instances, stupor has come on so profoundly, that 
there has been no awaking. 

32. There are instances related of sailors falling asleep on the 
gun-deck of their ships while in action. On the retreat from Mos- 
cow, the French soldiers would fall asleep on the march, and could 
only be aroused by the cry, " The Cossacks are coming !" Tortured 
persons are said to have slept upon the rack in the intervals of their 
torture. In early life, while engaged in a laborious country prac- 
tice, the writer not unfrequently slept soundly on horseback. 
These instances, and others, show the imperative demand which 
nature makes for rest in sleep. 

31. Amount of sleep in different persons? Cases? Frederick the Great? Bonaparte? 
Instances oflong deprivation of sleep? 

32. Instances of sailors ? French soldiers? During torture ? 



TABLE OF THE PRINCIPAL MUSCLES. 
(See Plate 9, Page 30.) 



The Head. 



— — Oc-cipl-to— fron-talis, moves the scalp and eyebrow* 

— — Or-bic-u-la'ris pal/pe-brae, closes the eye. 

-— Levator pal'pe-brae, opens the eye. 

- —The Recti muscles (four in number) move the eye-ball. 

The Neck. 

Sea le'ni muscles move the r.eck from side to side. 

The Trunk. 

" — Pec-to-ralis, moves the arm forwards. 

Hia-tis'si-mus dor' si, moves the arm backwards. 

Tra-pe'zi-us, ) 

Ser-ra'tus mag' nus, > move shoulder-blade. 

Rhom-boi-de'us, i 

In-ter-cos'tals, move the ribs in respiration. 

E-rec'tor spi'nae, move the trunk backwards. 

The Upper Limb, 

Del'toid, raises the arm. 
Te'res ma'jor, lowers the arm. 
Sub-scap-u-la'ris, l rotate the _-,. 
Spi-na'tus, f rotate tne arm * 

Bi'ceps, bends forearm. 
Tri'ceps, straightens forearm. 

Flex^or car^pi ra-di-a'lis, \ 

Ex-ten'sor car-p\"?a-S-aais, f move the hand ' 
" " ul-na'ris, ; 

More than thirty muscles take part in moving the fingers. 

The Lower Limb. 

Il-i'a-cus, ) 

Pec^fn^" 18 ' m ° Ve thethigb f0rwanl8 - 
Ad-duc / tor, ) 

pVr-i-farm'is, \ move the thigh to"***'** 

Sar-to'ri-us (from Sar'tor, a tailor) crosses one thigh over the other. 

Vas'tus, \ move the leg forwards - 

Gracilis, \ move the leg ****"&»• 
Tib-i-alis, ) 

oSSStSIWus, «ove the foot. 
So-le'us, ) 

Twenty muscles take part in moving the toes. 



THE MUSCLES. 



47 



4 



QUESTIONS FOR TOPICAL REVIEW. 

PAGE 

1. What can you state of the number and division of the muscles ? 31 

2. Describe the structure of the muscles 31 

3. Their arrangement in pairs and consequent action 32 

4. What is the difference between the motion called flexion and that called extension ?. . 32 

5. Describe their action, and state which are the more powerful 32 

6. What is the difference between voluntary and involuntary muscles ? 32 

7. Illustrate the difference between the two — 32 

8. State all you can of the tendons or sinews 33 

9. What is meant by contraction of the muscles ? — 34 

10. In how many and what ways may contraction be effected ? 34 

11. What is stated of after-death contraction ? 34 

12. Why cannot a muscle in life continue contracted a long time ? 35 

13. How then can the constant beating of the heart be explained ? 35 

14. How does the strength of a man compare with that of a horse ? 35 

15. What can you state' in regard to the relative strength of animals ? 35, 36 

16. What, in relation to physical strength ? 36 

17. What, in relation to physical degeneracy ? 36 

18. What, in relation to the importance of exercise ? 36, 37 

19. What is the effect of exereise upon the heart, skin, and appetite ? 37, 38 

20. How does exercise affect the current of the body's circulation ? 37 

21. How does judicious exercise affect the muscles ? 38 

22. What is stated of violent and spasmodic exercise ? 38 

23. Of the exercise of walking? 39 

24. Of running, leaping, and other modes of exercise ? .'. 39 

25. Of physical culture, in connection with out-door exercises ? 40 

26. What are the results of excessive exercise ? 40 

27. Of the importance of gymnastics in our schools and colleges ? 41 

28. Of the importance of rest from labor or exercise ? 44 

29. What processes take place during sleep ? 44 

30. What about the amount of sleep required ? 44 

31. What effects follow insufficient sleep ? 45 

32. Illustrate nature's demand for sleep 45 



OH.AJPTE3R III. 

The Integument, or Skin. 

The Integument — Its Structure — The Nails and Hair — The Complexion — Trt 
Sebaceous Glands — The Perspiratory Glands — Perspiration and its Uses-- 
Importance of Bathing — Different kinds of Baths — Manner of Bathing— 
The Benefits of the Sun — Importance of Warm Clothing — Poisonous 
Cosmetics. 

1. The Skin. — The skin is the outer covering of the body. The 
parts directly beneath it are very sensitive, and without its protec- 
tion life would be an agony, as is shown whenever by accident the 
skin is broken or torn off, the bared surface being very tender, and 
sensitive even to exposure to the air. Nature has provided the 
body with a garment that is soft, pliable, close-fitting, and very 
thin; and yet sufficiently strong to enable us to come in contact 
with the objects that surround us, without inconvenience or 
suffering. 

2. The Structure of the Skin. — When examined under the 
microscope, the skin is found to be made up of two layers — the 
outer and the inner. The inner one is called the cutis, or true 
skin ; the outer one is the epidermis, or scarf-skin. The latter is 
also known as the cuticle. These two layers are closely united, but 
they may be separated from each other. Tins separation takes 
place whenever, from a burn, or other cause, a blister is formed; a 
watery fluid is poured out between the two layers, and lifts the 
epidermis from the true skin. Of the two layers, the cuticle is the 
thinner in most parts of the body, and has the appearance of a 
whitish membrane. It is tough and elastic, is without feeling, 
and does not bleed when cut. Examine it more closely, and we 

1. What is the skin? Parts directly beneath? What is shown? 

2. Microscopic examination? What is the cutis? The cuticle? Their union? How 
separated ? What further is said of the cuticle ? 



THE INTEGUMENT, OR SKIN. 49 

observe that it is composed of minute flat cells, closely compacted, 
and arranged layer upon layer. 

3. The outer layer, the epidermis, is constantly being worn out, 
and falls from the body in the form of very fine scales. It is, also, 
continually forming anew on the surface of the inner layer. Its 
thickness varies in different parts of the body.* Where exposed to 
use, it is thick and horn-like, as may be seen on the soles of the 
feet, or on the palms of the hands of those who are accustomed to 
perform much manual labor. This is an admirable provision for 
the increased protection of the sensitive parts below the skin 
against all extraordinary exposure. Even the liabilities of these 
parts to injury, are thus kindly provided for by " the Hand that 
made us." {Read Note i.) 

4. The cutis, or true skin, lies beneath the epidermis, and is its 
origin and support. It is firm, elastic, very sensitive, and is freely 
supplied with blood-vessels. Hence, a needle entering it not only 
produces pain, but draws blood. It is closely connected with the 
tissues below it, but may be separated by means of a sharp instru- 

* Like all other parts of the body, the scarf-skin is constantly being worn 
out ; it dries, shrivels, and falls from the body in the form of fine flakes, 
or scales. In the scalp, these scales form the ' ' dandruff. " As fast as it wears 
away it is renewed from beneath. This seemingly simple process is very im- 
portant, for by it a uniform thickness is secured to the covering of the body. 
If it were otherwise, this covering would grow thicker as it grew older, like the 
bark of a tree, until it became unwieldy; it would prevent perspiration also, 
and this, as we shall see, would be fatal to life. The growth of the true skin 
is provided for in the blood-vessels which abound in it. 

1. The Renewal of the Cuticle. — The skin is not a permanent sheath, 
but is, as it were, always wearing out and rubbing off, and new skin is always 
rising up from underneath. A snake leaves off his whole skin at once, as we 
leave off a suit of clothes or a dress, and sometimes we may find his whole cast- 
off covering turned inside out, just as he crept out of it. In man, generally, 
we do not notice the dead particles of the skin as it wears off ; but where 
the cuticle is pretty thick, as on the soles of the feet, we can see it peel off in 
little rolls whenever we wash the feet in hot water. After scarlet fever, too, 
sometimes the dead skin comes off in great flakes, and from *he hands almost; 
like the fingers of a glove. — Berners. 

3. Wearing out of the cuticle? What then? Variety in thickness of cuticle? Ho\» 
accounted for ? 

4. Location and office of the cutis ? What further is said of it? Papillae ? Touch ? 

3 



50 



THE INTEGUMENT, OR SKIN. 



merit. The surface of the cutis is not smooth, but covered here and 
there with minute elevations, called papillce. These are arranged 
in rows, or ridges, such as those which mark the palm and thumb ; 
their number is about 80 to the square line (a line being one-twelfth 
of an inch). These papillce contain blood-vessels and nerves also, 
and are largely concerned in the sense of touch; hence they are 
abundant where the touch is most delicate, as at the ends of the 
fingers. 

5. The Nails and Hair.— These are modified forms of the 
cuticle. The nail grows from a fold of the cuticle at the root, and 
from the under surface. As fast 

as it is formed, it is constantly 
being pushed outward.* The 
rapidity of its growth can be 
ascertained by filing a slight 
groove on its surface, and notic- 
ing how the space between it 
and the root of the nail in- 
creases, in the course of a few 
weeks. When the nail is re- 
moved by any accident, it will be 
replaced by a new one, if the root 
be not injured. {Notes 2 and '6. ) 

6. The hairs are produced in 
a similar manner ; the skin form- 
ing depressions, or hair sacs, from 
the bottom of which they grow 
and are nourished (Fig. 17). 
They are found, of greater or 
less length, on almost all parts of the surface, except the palms of 
the hands and soles of the feet. On certain parts of the body, they 




a, 6. The Root of a Hair highly magnified. 
1, 2, 3. The skin forming the hair sac 4. Se- 
baceous glands. 5. The hair sae. 
c. Transverse Section of a Hair highly 

MAGNIFIED. 



* The practice of biting the nails should be avoided not only because 
of the ugly shape which is produced, but because it impairs the sense of touch 
in the ends of the fingers. In paring the nails, let them remain long enough 



5. What are the nails and hair? The growth of the nail? The rapidity of its growth! 
Accident to the nail ? 

6. How are the hairs produced? Difference in their length? 



THE INTEGUMENT, OR SKIN. 51 

grow to great length ; on other parts they are so short, that they do 
not rise beyond the hair-sac from which they grow. 

7. The bulb, or root, from which the hair arises, is lodged in a 
small pouch, or depression in the skin. The shaft is the part which 
grows out beyond the level of the skin. Its growth is altogether in 
one direction, in length alone. The outer part of the hair is quite 
firm, while its interior is softer, and supplies the nutriment by 
which it grows. The hair is more glossy in health than at other 
times. 

8. The nail serves as a protection to the end of the finger, and 
also enables us to grasp more firmly, and to pick up small objects. 
The hair, too, is a protection to the parts it covers. On the head, 
it shields the brain from extremes of heat and cold, and moderates 
the force of blows upon the scalp. On the body, it is useful in 
affording a more extensive surface for carrying off the perspira- 
tion. 

to nearly cover the pulp of the finger. Avoid scraping either surface of the 
iail ; do not injure the ' ' quick. " 

2. The Life of the Cells of the Body "The life of the body 

is long under fortunate circumstances ; that of our cells is short. We all 
know that the surface of the body is covered by layers of cells. The super- 
ficial layers are in loose connection ; they are cells in old age. The friction of 
our clothing daily removes an immense number of them. A cleanly person 
who uses sponge and towel energetically every day rubs off a still greater 
quantity. 

" We swallow ; our tongue acts in speaking ; drink and food pass this way. 
Now, the mucous membrane of the mouth is covered with layers of cells. 
Here, also, many thousand senile cells are rubbed off daily. And so on 
through the entire digestive tract. An immense number of cells — these living 
3orner-stones of the body — is thus lost daily. 

" To show the duration of life in one kind of cell, let us turn to the human 
nail. The latter, growing from a furrow of the skin, is made up of skin-cells. 
In the depth of the furrow, youth prevails ; at the upper margin — which wo 
trim — old age. Berthold proved that a nail-cell lives four months in summer 
and five in winter. A person dying in his 80th year, has changed his nail 
200 times, at least — and the nail appeared such an inanimate, unvarying 
thing ! No other cells, we believe, have a life nearly so long as that of the 
nail. " — Compendium of Histology by Heinrich Frey. 



7. Root of the hair? Shaft ? Firmness and softness of the hair? 

8. Office of the nail? Of the hair? Give the illustrations. 



52 



THE INTEGUMENT, OR SKIN. 



9. Complexion. — In the deeper cells of the cuticle lies a pig- 
ment, or coloring-matter, consisting of minute colored grains. On 
this pigment complexion depends; and its presence, in less or 
greater amount, occasions the difference of hue that exists between 
the light and the dark races of men, and between the blonde and 
the brunette of the white races. Freckles are due to an irregular 
increase of this coloring matter. 

10. The sun has a powerful influence over the development of 
ohis pigment, as is shown by the swarthy hue of those of the white 
race who have colonized in tropical climates. It is also well illus- 
trated by the fact, that among 

the Jews who have settled in 
northern Europe, there are many 
who are fair-complexioned, while 
those residing in India are as dark 
as the Hindoos around them. 

11. An Albino is a person who 
may be said to have no com- 
plexion; that is, there is an en- 
tire absence of coloring matter 
from the skin, hair, and iris of 
the eye. This condition exists 
from birth, and more frequently 
occurs among the dark races, and 
in hot climates, although it has 
been observed in almost every 
race and clime. 

12. Sebaceous Glands. — In all parts of the surface where the 
hairs grow, are to be found the sebaceous, or oil-producing glands. 
These glands are little rounded sacs, usually connected with the hair- 
bulbs ; and upon these bulbs they empty their product of oil, which 
acts as a natural dressing for the hair (4, Fig. 17). A portion of 
the sebaceous matter passes out upon the surface, and prevents the 
cuticle from becoming dry and hard. The glands situated upon the 

9. On what does the complexion depend ? Light and dark races ? Freckles? 

10. Influence of the sun ? How illustrated? Jews? 

11. What is an Albino? Where are'Albinos found? 

12. What are sebaceous glands ? How do they act ? Sebaceous glands of the face ? How 
do they act? 




Fig. 18. 



-Showing a Hair and Section of 
Skin highly magnified. 



THE INTEGUMENT, OR SKIN. 53 

face and forehead open directly upon the skin. In these, the seba- 
ceous matter is liable to collect, and become too hard to flow off 
naturally. 

13. These glands on the face and forehead frequently appear on 
the faces of the young as small, black points, which are incorrectly 
called "worms." It is true, that occasionally living animalcules 
are found in this thickened sebaceous matter, but they can only be 
detected by the aid of the microscope. This sebaceous matter acts 
not only to keep the skin flexible, and furnish for the hair an oily 
dressing, but it especially serves to protect the skin and hair from 
the acridity arising from the perspiration. 

14. The Perspiratory Glands. — The chief product of the skin's 
action is the perspiration. For the formation of this, there are fur- 
nished countless numbers of little sweat-glands in the true skin. 
They consist of fine tubes, with globe-like coils at their deeper ex- 
tremity. Their mouths or openings may be seen with an ordinary 
magnifying-glass, upon the fine ridges which mark the fingers. 
These tubes, if uncoiled, measure about one-tenth of an inch in 
length. In diameter they are about one three-hundredth of an 
inch, and upon parts of the body there are not far from three thou- 
sand of these glands to the square inch. Their whole number in 
the body is, therefore, very great ; and it is computed, if they 
were all united, end to end, their combined measurement would ex- 
ceed three miles. 

15. The Sensible and Insensible Perspiration. — The pores of 
the skin are constantly exhaling a watery fluid ; but, under ordi- 
nary circumstances, there is no moisture apparent upon the surface, 
for it evaporates as rapidly as it is formed. This is called insen- 
sible perspiration. Under the influence of heat or exercise, however, 
this fluid is formed more abundantly, and appears on the surface in 
minute, colorless drops. It is then termed sensible perspiration. 

16. Water is the chief component of this fluid, there being about 
ninety-eight parts of water to two parts of solid matter. The quantity 
escaping from the body varies greatly, according to the temperature 

13. Black points, called worms? Animalcules? Service performed by sebaceous matter ': 

14. Perspiration ? Sweet glands ? Of what do they consist? Dimension of the tubes? 

15. What is sensible perspiration ? Insensible perspiration ? 

16. Components of perspiration ? Upon what does perspiration depend ? Amount ot 
perspiration daily ? 



54 THE INTEGUMENT, OR SKIN. 

of the air, the occupation of the individual, and other circum- 
stances. The average daily amount of perspiration in the adult is 
not far from two pints, or more than nine grains each minute. 

1.7. The Uses of the Perspiration. — Besides liberating from 
the blood this large amount of water, with the worn-out matter 
it contains, the perspiration serves to regulate the temperature 
of the body. That is to say, as evaporation always diminishes 
temperature, so the perspiration, as it passes off in the form of fine 
vapor, cools the surface. Accordingly, in hot weather this function 
is much more active, and the cooling influence increases in propor- 
tion. When the air is already charged with moisture, and does not 
readily receive the vapor of the body, the heat of the atmosphere 
apparently increases, and the discomfort therefrom is relatively 
greater. 

18. The importance of perspiration is shown by the effects that 
often follow its temporary interruption, namely, headache, fever, 
and the other symptoms that accompany "taking cold." When 
the perspiration is completely checked, the consequences are very 
serious. Experiments have been performed upon certain smaller 
animals, as rabbits, to ascertain the results of closing the pores of the 
skin. When they are covered by a coating of varnish impervious 
to water and gases, death ensues in from six to twelve hours — the 
attendant symptoms resembling those of suffocation. {Read Note 3.) 



3. On Taking Cold. — " Of all the things to which humanity is liable, 
there is none which recurs more frequently, and whose consequences are more 
troublesome and often dangerous, than l taking cold. 11 Some persons have 
quite a faculty for taking cold, while others do so but rarely. And yet the 
Dne does not argue delicacy of constitution, or the other strength. The body 
of man has a constant and agreeable temperature in health, the variation being 
slight. In fact, any great variation is incompatible with health, and consti- 
tutes disease. Clothes, by preventing the radiation away of heat from the 
surface, retain it, and so the feeling of cold is not so great — that is, the surface 
does not become so cold. Clothes are non-conductors of heat when dry; but 
let them be saturated with water, and unless the loss of heat be met by 
increased production, there is a lowering of the body temperature — • taking 
cold.' Thus, if exertion be continued, and more heat is produced to meet the 



17. What does perspiration set free from the blood? What other service does perspiration 
perform ? Explain the process. 

IS. Etfect of interruption of excretion? What experiments a-e mentioned? 



THE INTEGUMENT, OR SKIN. 55 

19. It is related that, at the coronation of one of the Popes, about 
three hundred years ago, a little boy was chosen to act the part of 
an angel; and, in order that his appearance might be as gorgeous as 
possible, he was covered from head to foot with a coating of gold- 
foil. He was soon taken sick, and although every known means 
were employed for his recovery, except the removal of his fatal 
golden covering, he died in a few hours.* 

20. The Importance of Bathing. — From these considerations, 
it is evident that health must greatly depend upon keeping the skin 
clean. " He who keeps the skin ruddy and soft, shuts many gates 
against disease." For as the watery portion of the perspiration 
evaporates, the solid matter is left behind. There, also, remain the 
scales of the worn-out cuticle, and the excess of sebaceous matter. 
In order to secure the natural action of the skin, these impurities 
require to be removed by the frequent application of water. {Read 
Note 4. ) 

loss until a change of dry clothing is procurable, no injury results. But let 
the wet clothes be worn without a corresponding heat production, as when 
children sit down in school in their wet clothes, or the shop-boy stands in his 
moist garments ; then there is a rapid loss of heat, a lowering of the body 
temperature, and a cold is 'caught.' So is a cold caught by wet feet, when 
the heat is radiated away from the feet ; if exercise be continued the cold is 
not experienced. A damp bed gives cold because the moist bedclothes conduct 
away the heat, and the body temperature is lowered." — Fothergill on the Main- 
tenance of Health. 

* A clogged action of the skin is disastrous in many diseases, but 
especially those attended by an eruption, or " breaking out." One of these — 
small-pox — is exceedingly fatal among the American Indians, whole tribes hav- 
ing been swept away by it. And this is explained by the fact that they habit- 
ually close their pores by covering their bodies with bears' grease, as a protec- 
tion against the cold, and with earthy paints as a means of decoration. 

4. Bathing. — " When the civilization of Egypt, Greece, and Kome faded, 
the world passed through dark ages of mental and physical barbarism. For a 
thousand years there was not a man or woman in Europe that ever took a 
bath, if the historian of those times, Michelet, is to be believed. No wonder 
that there came the wondrous epidemics of the middle ages, which cut off one- 
fourth of the population of Europe — the spotted plague, the black death, sweat- 
ing sickness, and the terrible mental epidemics which followed in their train— 



19. Give the story in relation to the hoy covered with gold foil. 

20. Give the quotation. Perspiration ? 



56 THE INTEGUMENT, OR SKIN. 

21. In warm climates, and during hot weather, bathing is espe- 
cially necessary. For a .person in good health, a daily cold bath is 
advisable. To this should be added occasionally a warm bath, with 
soap, water alone not being sufficient to remove impurities of a 
greasy nature. Soap facilitates this, by forming with such sub- 
stances a chemical mixture, which is taken up by water, and by it 
removed from the body. {Read Note 5.) 

the dancing mania, the mewing mania, and the biting mania. Not only their 
persons, but their houses were uncleanly, even in the classes that were well- 
to-do. Filth, instead of being abhorred, was almost sanctified. " — Lyon Play- 
fair. 

5. An Imaginary Conversation on Baths and Bathing. — "I have 
often amused myself, by fancying one question which an old Roman emperor 
would ask, were he to rise from his grave and visit the sights of London under 
the guidance of some minister of state. The august shade would, doubtless, 
admire our railroads and bridges, our cathedrals and our public parks, and 
much more of which we need not be ashamed. But after a while, I think, he 
would look round, whether in London, or in most of our great cities, inquir- 
ingly and in vain, for one class of buildings, which in his empire were wont to 
be most conspicuous and splendid. 'And where,' he would ask, 'are your 
public baths ? ' And if the minister of state who was his guide should answer — 
' great Csesar, I really do not know. I believe there are some somewhere in 
some out-of-the-way place ; and I think there have been some meetings lately, 
and an amateur concert, for restoring, by private subscriptions, some baths and 
wash-houses which had fallen to decay. And there may be two or three more 
about the metropolis ; for parishes have power to establish such places, if they 
think fit, and choose to pay for them out of the rates : ' — Then, I think, the 
august shade might well make answer — ' We used to call you, in old Rome, 
northern barbarians. It seems that you have not lost all your barbarian 
habits. Are you aware that, in every city in the Roman empire, there were, 
as a matter of course, public baths open, not only to the poorest freeman, but 
to the slave, usually for the payment of the smallest current coin, and often 
gratuitously ? Are you aware that in Rome itself, millionaire after millionaire, 
emperor after emperor, built baths, and yet more baths ; and connected with 
them gymnasia for exercise, libraries, and porticoes, wherein the people might 
have shade and shelter, and rest ? Are you aware that these baths were of 
the most magnificent architecture, decorated with marbles, paintings, sculp- 
tures, fountains, what not ? And yet I had heard, in Hades down below, 
that you prided yourselves here on the study of the learned languages. " — 
Rev. Charles Kingsley on the Air-mothers. 



21. AWution in warm climates? What advice is given? 



THE INTEGUMENT, OR SKIN. 57 

22. There is a maxim by the chemist Liebig, to the effect, that 
the civilization of a nation is high, in proportion to the amount of 
soap that it consumes ; and that it is low, in proportion to its use of 
perfumes. In some degree, we may apply the same test to the 
refinement of an individual. The soap removes impurity ; the per- 
fume covers, while retaining it. {Read Notes 6 and 7. ) 

23. The Different Kinds of Baths. — All persons are not alike 
able to use the cold bath. When the health is vigorous, a prompt 
reaction and glow upon the surface will show that it is beneficial. 
Where this pleasurable feeling is not experienced, but rather a chill 
and sense of weakness follows, we are warned that the system will 
not, with impunity, endure cold bathing. Most persons experience 
the best results when the water is about the temperature of the 
body— "blood-heat." 

24. It should also be borne in mind, that the warm or hot bath 

6. Care of the Skin and Nails. — Much ignorance prevails amongst the 
public as to the use of soap and water. Those who have very sensitive skins 
should use soft water, for the face at all events, and the best water, if it can 
be had, is rain-water with the cold taken off it. Nor is it every kind of soap 
which is tolerated by such persons ; probably the safest soaps are, not those 
which are said to contain, but those which really do contain, a large portion 
of glycerine. 

The culture of the nails, which when perfect constitute so great a beauty, 
is of much importance ; but the tendency is to injure them by too much atten- 
tion. The scissors should never be used, except to pare the free edges when 
they have become ragged or too long, and the folds of scarf skin which over- 
lap the roots should not, as a rule, be touched. The upper surfaces of the 
nails should on no account be touched with the knife, as it is so often done, 
the nail brush being amply sufficient to keep them clean, without impairing 
their smooth and polished surfaces. — People's Magazine. 

7. On Scents. — "They are the only resource of rude and dirty times 
against offensive emanations from decaying animal and vegetable substances, 
from undrained and untidy dwellings, from unclean clothes, from ill-washed 
skins, and from ill-used stomachs. The scented handkerchief, in these cir- 
cumstances, takes the place of the sponge and the bath ; the pastile hides the 
want of ventilation ; the otto of roses seems to render the scavenger unneces- 
sary ; and a sprinkling of musk sets all other smells and stinks at defiance. " — 
Johnston. 

22. Liebig's maxim ? What further is added ? 

23. What is said about cold bathing? 

24. What is said about warm bathing? 



58 THE INTEGUMENT, OR SKIN. 

cannot be continued so long, or repeated so frequently, as the cold, 
on account of the enervating effect of unusual heat so applied to the 
body. For persons who are not in robust health, one warm bath 
each week is sufficient. Such persons should be careful to avoid 
every extreme in reference to bathing, clothing, and whatever 
greatly affects the action of the skin. 

25. Sea-bathing is even more invigorating than fresh- water 
bathing. Those who cannot endure the fresh water, are often bene- 
fited by the salt-water baths. This may be accounted for, in part, 
by the stimulant action upon the surface, of the saline particles of 
the sea- water; but the exciting scenes and circumstances of sea- 
bathing also exert an important influence. The open-air exercise, 
the rolling surf, the genial weather, and usually the cheerful com- 
pany, add to its intrinsic benefits. {Read Note 8. ) 

26. Time and Manner of Bathing. — A person in sound health 
may take a bath at almost any time, except directly after a full 
meal. The most appropriate time is about three hours after a 

8. The Proper Use of Sea-bathing. — "The length of time during 
which a person should remain in the water necessarily varies according to the 
age, sex, and constitutional strength of the bather. Due regard should also 
be had to the state of the weather and season of the year. 

" In the case of children, five, gradually extended to ten minutes ; of women, 
ten to fifteen minutes ; and of men, a quarter of an hour or more, is a fair 
average period. There are some people, doubtless, to whom these periods will 
appear insufficient, and who insist on remaining so long in the water that their 
skin becomes cold and blue, their teeth begin to chatter, and a condition of 
general exhaustion comes on ; people, in short, who have the ' most ' for their 
money, like the countryman who grumbled at having been conveyed thirty 
miles in about half-an hour by an express train, on the score that the length 
of time occupied in the journey was not proportionate to the fare that he had 
paid. On entering the water, the bather should immerse the whole of the 
body two or three times, so as to get the action of the shock from the cold 
water distributed over its entire surface. There should be no hesitancy, no 
dabbling about with the feet, but a good plunge at once into the next wave 
that washes in. Upon coming out of the water the bather should dry the 
body with good rough towels, dress quickly, and take a brisk walk for a short 
distance. If there be any feeling of exhaustion or nervous depression, a little 
food or drink should be taken." 



25. What is said about sea-bathing? 

26. What is said as to the time and manner of bathing? 



THE INTEGUMENT, OR SKIN. 59 

meal, the noon-hour being probably the best. For the cold bath, 
taken rapidly, no time is better than immediately after rising. 
Those beginning the use of cold baths should first try them at 70° 
Fahrenheit, and gradually use those of a lower temperature. From 
five to twenty minutes may be considered the proper limit of time 
to remain in a bath; but a sensation of chilliness is a signal to 
withdraw instantly, whether at home, or at the sea-side. Two sea- 
baths may be taken daily ; one of any other kind is sufficient. 

27. The body should be warm, rather than cold, when stepping 
into the bath; and after it, the skin should be thoroughly dried 
with a coarse rowel. It is best to continue friction until there is a 
sensation of warmth or " glow " throughout the entire surface. This 
reaction is the test of the good effects of the bath. If reaction is> 
still incomplete, a short walk may be taken, especially in the sun- 
shine. It is very congenial, however, both to health and comfort, 
to rest for a short time directly after bathing, or to take some light 
refreshment. This is better than severe exercise or a full meal. 

28. Bathing among the Ancients. — The Eomans and other 
nations of antiquity made great use of the vapor-bath as a means of 
preserving the health, but more particularly as a luxury. Their 
method was not unlike that employed in some parts of Europe at 
the present day. The public baths of Rome and other cities are 
among the grandest and most interesting monuments of ancient 
luxury and splendor; and from their ruins have been recovered 
some of the most beautiful works of art. 

29. The Thermae, as the baths of Eome were called, were of 
great extent, built very substantially, and ornamented at vast ex- 
pense. They were practically free to all, the cost of a bath having 
been less than a cent. It is related that some persons bathed seven 
times a day. After the bath their bodies were anointed with per- 
fumed oil. If the weather was fine, they passed directly from the 
Thermae into the gymnasium, and engaged in some gentle exercise pre- 
vious to taking the midday meal. Between two and three in the 
afternoon was the favorite hour for this ancient luxury. Swim- 
ming was a favorite exercise, and a knowledge of it was regarded as 

27. Condition of the body when bathing? Direction, after bathing? 

28. Bathing among the ancients ? Baths of Rome ? 

29. After the bath ? Swimming among the ancients? 



60 THE INTEGUMENT, OR SKIN. 

necessary to every educated man. Their common expression, when 
speaking of an ignorant person, was, " He can neither read nor 
swim." 

30. The Sun -Bath. — Some also were accustomed daily to 
anoint themselves, and lie or walk in apartments arranged for the 
purpose, with naked bodies exposed to the direct rays of the sun. 
There is an interesting allusion to this practice, in a letter of the 
younger Pliny to the historian Tacitus, describing the destruction 
of Pompeii by an eruption of Vesuvius. " My uncle " (Pliny the 
elder) "was at that time in command of the fleet at Misenum. 
On the 24th of August, about one in the afternoon, my mother 
desired him to notice a cloud which seemed of unusual shape and 
dimensions. He had just returned from taking the benefit of the sun, 
and after a cold bath, and a slight repast, had retired to his study." 
Then follows a description of the destruction of Pompeii, and the 
death of the elder Pliny. 

31. We may judge somewhat of the benefits of the sun, by 
observing the unnatural and undeveloped condition of plants and 
animals which are deprived of light. Plants become blanched and 
tender ; the fish of subterranean lakes, where the light of day never 
enters, are undersized, and have no eyes ; tadpoles kept in the dark 
do not develop into frogs ; men growing up in mines are sallow, 
pale, and deformed. Besides the well-known effect of solar light in 
tanning the skin, it also makes it thicker and better able to resist 
exposure; though the complexion may be thereby injured, the 
health gained more than compensates for the loss of beauty. " To 
make good the loss of the lily, where the sun has cast his ray, he 
seldom fails to plant the rose." {Read Notes 9 and 10.) 

9. Light Influences Growth and Health. — "I have several times 
taken two potatoes which were as nearly as possible alike, and placed one 
under a bell-glass through which the light could pass, and the other under a 
similar cover rendered opaque by several coats of black paint. Sprouting 
went on unchecked under the translucent glass, while it was always notably 
retarded and sometimes prevented in the potato under the dark glass. Milne 
Edwards, a distinguished French physiologist, performed a series of experi- 
ments which showed that tadpoles when deprived of light did not develop 



30. The sun-bath ? The story of Pliny ? 

31. Benefit of the sun? Effect upon plants ? Skin? 



THE INTEGUMENT, OR SKIN. 61 

32. Clothing.* — In reference to clothing, we are far more apt, in 
**ur changeful climate, to use too little than too much. An aphorism 
of Boerhaave, worth remembering, if not of adopting, is, " We 
should put off our winter clothing on midsummer's day, and put it on 
again the day after." He also says, " Only fools and beggars suffer 
from the cold ; the latter not being able to get sufficient clothes, 
the others not having the sense to wear them." The practice of 
axposing the limbs and necks of young children, for the alleged 

into the frog. I have several times repeated his experiments, and always with 
confirmatory results. On one occasion I prevented for one hundred and 
twenty-five days the development of a tadpole, by confining it in a vessel to 
which the rays of light had no access. On placing it in a receptacle open to 
the light, the process of transformation was at once begun, and was completed 
in fifteen days. The practical application of these and similar observations is 
this, that care should be taken both in health and disease to insure a sufficient 
amount of sunlight to the inmates of houses, and that it is impossible to rear 
well-formed, strong, and robust children unless attention is paid to this 
requirement." — Hammond on the Influence of Light. 

* Man is the only animal that requires clothing ; and as he advances 
from barbarism to civilization, more and more attention is paid to dress as a 
means of protection against cold. As a rule, more harm arises from using too 
little clothing than too much, especially in a changeful climate like our own. 

10. Light in the Sick-room. — "It is the unqualified result of all my 
experience with the sick, that second only to their need of fresh air is their 
need of light ; that, after a close room, what hurts them most is a dark room ; 
and that it is not only light, but direct sunlight they want. You had better 
carry your patient about after the sun, according to the aspect of the rooms, 
if circumstances permit, than let him linger in a room when the sun is off. 
People think that the effect is upon the spirits only. This is by no means the 
case. Who has not observed the purifying effect of light, and especially of 
direct sunlight, upon the air of a room ? Here is an observation within every- 
body's experience. Go into a room where the shutters are always shut (in a 
sick-room or a bed-room there should never be shutters shut), and though the 
room be uninhabited — though the air has never been polluted by the breath- 
ing of human beings, you will observe a close, musty smell of corrupt air — of 
air unpurified by the effect of the sun's rays. The mustiness of dark rooms 
and corners, indeed, is proverbial. The cheerfulness of a room— the usefulness 
of light in treating disease — is all-important. It is a curious thing to observe 
how almost all patients lie with their faces turned to the light, exactly as 
plants always make their way toward the light. "—Florence Nightingale's Notes 
on Nursing. 

32. Direction about clothing? Exposing limbs of children ? Clothing, night and day ? 



62 THE INTEGUMENT, OR SKIN. 

purpose of " hardening " them, is quite hazardous. It is not to be 
denied that some seem to be made tough by the process. But it is 
so only with the rugged children ; the delicate ones will invariably 
suffer under this fanciful treatment. As the skin is constantly act- 
ing, by night as well as by day, it is conducive both to cleanliness 
and comfort to entirely change the clothing on retiring for the 
night. The day-clothing should be aired during the night, and the 
bedding should be aired in the morning, for the same reason. 
{Read Notes II and 12.) 

11. Under-clothing and Bedding. — All clothing worn during the day 
should be removed at night. A practice prevails in tropical countries of shak- 
ing thoroughly every article of apparel just before it is placed on the body. 
The motive which prompts this comes from the fear lest a centipede or other 
lively and virulent specimen of natural history has hid itself somewhere within 
the folds of the garment. Even without the danger of wearing one's shirt in 
conjunction with such an intruder, it is an excellent practice to shake it and 
every other article of clothing thoroughly before putting them on. The gar- 
ments worn next to the skin should be changed before they become saturated 
with the secretions of the sebaceous glands. This can be accomplished by 
renewing them twice a week, though the majority of people only change them 
once in that period. Combe recommends to wear two sets of flannels, each 
being worn and aired by turns, on alternate days ; he likewise praises a prac- 
tice common in Italy, namely, instead of beds being made up in the morning 
the moment they are vacated, and while still saturated with the nocturnal ex- 
halations, the bed-clothes are thrown over the backs of chairs, the mattresses 
shaken up, and the window thrown open for the greater part of the day. This 
practice, so consonant with reason, imparts a freshness which is peculiarly 
grateful and conducive to sleep. Florence Nightingale, who never fails to 
speak plainly, says : " Feverishness is generally supposed to be a symptom of 
fever ; in nine cases out of ten it is a symptom of bedding. A real patient 
should have two beds, remaining only twelve hours in each ; on no account to 
carry his sheets with him." — Draper {in Part). 

12. Rules as to Clothing.— Protection against Cold. — For equal thick- 
nesses, wool is much superior to either cotton or linen, and should be worn for 
all under clothing. In cases of extreme cold, besides wool, leather or water- 
proof clothing is useful. Cotton and linen are nearly equal. 

Protection against Heat. — Texture has nothing to do with protection from 
the direct solar rays ; this depends entirely on color. White is the best color ; 
then gray, yellow, pink, blue, black. In hot countries, therefore, white or 
light-gray clothing should be chosen. In the shade the effect of color is not 
marked. The thickness and the conducting power of the material are the con- 
ditions (especially the former) which influence heat 



THE INTEGUMENT, OR SKIN. bd 

33. Poisonous Cosmetics. — The extensive use of cosmetics for 
the complexion is a fertile source of disease. The majority of these 
preparations contain certain poisonous mineral substances, chiefly 
lead. The skin rapidly absorbs the fine particles of lead, and the 
system experiences the same evil effects that are observed among the 
operatives in lead works and painters, namely, "painters' colic," 
and paralysis of the hands, called " wrist-drop." 

34. Certain hair-dyes also contain lead, together with other 
noxious and filthy ingredients. These do not work as great harm 
as the cosmetics, since they are purposely kept away from the skin ; 
but they rob the hair of its vitality. Eye-washes, too, are made 
from solutions of lead, and many an eye has been ruined by their 
use. Thev deposit a white metallic scale on the surface of the eye, 
which, when in front, permanently blurs the sight. 

The body should not only be so protected by its covering as to be kept from 
rain and damp, but the clothing must be so ventilated that the emanations 
from the skin shall not accumulate. The wearing of the unventilated beaver 
hat, or fur cap, is a ready method of suppressing the natural growth of the 
hair, and of causing the retention of that effete epithelial scale commonly 
called scurf, or dandruff. The wearing of tightly-fitting water-proof coats can- 
not be habitually practiced without danger to the wearer ; the very painful 
and troublesome ailment, rheumatism, has in many persons been produced by 
this manner of locking in the excretions of the surface. — Dr, B. W. Richardson. 



33. Cosmetics ? Painters' colic ? 



64 THE INTEGUMENT, OR SKIN. 



QUESTIONS FOR TOPICAL REVIEW. 

PAGE 

1. What are the characteristics of the skin, and what office does it perform ? 48 

2. What can you state of the structure of the skin ? 48 

3. Describe the cuticle and tell its use 49 

4. Describe the cutis or true skin and tell its use 49 

5. What can you state of the nature and growth of the nail ? 50 

6. Explain growth of the hair ? 50 

7. Of the nature and growth of the hair? 50, 51 

8. Of the offices performed by the nails and hair ? 51 

9. What is an Albino ? 52 

10. How is the difference in complexion in different persons accounted for ? 52 

11. How is the presence of freckles accounted for? 52 

12. How does Nature provide a dressing for the hair? 52 

13. What is the composition of perspiration? 53 

14. What other service do the sebaceous glands perform ? 53 

15. State what you can of the perspiratory glands and their number ? 53 

16. What is the difference between sensible and insensible perspiration ? 53 

17. State the uses and importance of perspiration ? 54 

18. What impurities gather naturally on the skin ? 54 

19. What the effects of stopping perspiratory action ? 54, 55 

20. Repeat what is said of the importance of bathing? 55, 56 

21. Different kinds of baths for different individuals 57 

22. When should we indulge in cold, warm, and sea-bathing ? 58 

23. What is the effect in each case ? 58 

24. What directions are given as to the time and manner for bathing ? 58, 59 

25. What is related of bathing among the ancients? 59 

26. Directions after the bath ? 59 

27. What is related to show the antiquity of sun-bathing ? 60 

28. What are the effects of sun-bathing ? 60 

29. What directions are given in relation to clothing the body ? 61 

30. What can you state of poisonous cosmetics ? 63 

31. Of hair-dyes and eye-washes 63 



chapter rv. 

The Chemistry of Food. 

The Source of Food — Inorganic Substances — Water — Salt — Lime — Iron — Or- 
ganic Substances — Albumen, Fibrin, and Caseine — The Fats or Oils — The 
Sugars, Starch, and Gum — Stimulating Substances — Necessity of a Regu- 
lated Diet. 

1. The Source of Food. — The term food includes all those 
substances, whether liquid or solid, which are necessary for the 
nourishment of the body. The original source of all food is the 
earth, which the poet has fitly styled the " Mother of all living." 
In her bosom, and in the atmosphere about her, are contained all 
the elements on which life depends. But man is unable to obtain 
nourishment directly from such crude chemical forms as he finds in 
the inorganic world. They must, with a few exceptions, be pre- 
pared for his use, by being transformed into new and higher com- 
binations, more closely resembling the tissues of his own body. 

2. This transformation is effected, first, by the vegetable world. 
But all plants are not alike useful to man, while some are absolutely 
hurtful. Accordingly, he must learn to discriminate between that 
which is poisonous and that which is life-supporting. Again, all 
parts of the same plant or tree are not alike beneficial : in some, 
the fruit ; in others, the leaves ; and in others, the seeds only are 
sufficiently refined for his use. These he must learn to select ; he 
must also learn the proper modes of preparing each kind for his 
table, whether by cooking or other processes. {Read Note i.) 

1. The Circle of Organic Life. — Man, as an animal, is chemically an 
oxidizing agent, reducing again to primitive forms the principles built up by 
the vegetable world, and taken in by him either directly as vegetables, or in- 
directly in the shape of the material of other animals. Without vegetable life 



1. The term food ? Source of food ? Need of preparing food ? 

2. Usefulness and hurtfulness of plants ? What then must man do ? Parts of the same 
plant or tree ? 



66 ' THE CHEMISTRY OF FOOD. 

3. Again, certain forms of the vegetable creation which are 
unfit, in their crude state, for man's food, and which he rejects, are 
chosen as food by some of the lower animals, and are, by them, 
made ready for his use. Thus the bee takes the clover, that man 
cannot eat, and from it collects honey. The cattle eat the husks of 
corn and the dried grass, that are by far too coarse for man, and in 
their own flesh convert them into tissues closely resembling his 
muscular tissue. In this way, by the aid of the transforming pro- 
cesses of the vegetable and animal creations, the simple chemical 
elements of the mineral kingdom are elaborated into our choice 
articles of food. {Read Note 2. ) 

animals could not exist, and never could have existed ; side by side they grow 
and nourish, indispensable to each other's existence ; the tree breaking up the 
exhaled carbonic acid of the animal — the carbon being stored up in its increas- 
ing mass — while the oxygen is returned again, free and uncombined, to the 
atmosphere for the respiratory needs of the animal world. Round and round 
go the elementary bodies in ceaseless change of form, nevertheless never more 
than they were at first and will be at the last — the atomic material of this 
planetary sphere being ever absolutely the same in amount. The material of 
the bodies of Saul and his sons, when burnt by the men of Israel after their 
ignominous exposure at Bethshan, in consequence of their defeat on Mount 
Gilboa, are circulating amongst us still ; it served others before them, and has 
formed part of thousands since. It is quite within the bounds of chemical 
possibility that some of the atoms contained in the fated apple of Eve, may 
have lain in the material of the apple which revealed to Newton the law of 
gravitation. " — Fothergill on the Maintenance of Health. 

2. The Food Circle in Nature. — " There are the same ultimate elements 
in flesh as in flour, the same in animals as in vegetables. The vegetable draws 
food from the soil and from the air. and being fully matured, it or some part 
of it is eaten by the animal. But in completing the circle, the vegetable re- 
ceives and thrives upon the animal itself, in whole or in part, or the refuse 
which it daily throws off. The very bones of an animal are by nature or man 
made to increase the growth of vegetables and really to enter into their struc- 
ture ; and being again eaten, animals may be said to eat their own bones, and 
live on their own flesh. Hence there is not only an unbroken circle in the 
production of food from different sources, but even the same food may be 
shown to be produced from itself. Surely this is an illustration of the fable of 
the young Phoenix arising from the ashes of its parent." — Edward Smith on 
Foods. 



3. Certain forms of vegetable creation? Example of the bee? Cattle? The Uv 
ference ? 



THE CHEMISTRY OF .FOOD. 67 

4. Inorganic Substances. — The substances we use as food are 
classified as organic and inorganic. By organic substances are meant 
those derived from living forms, such as vegetables and animals. 
Inorganic substances are those simpler inanimate forms which be- 
long to the mineral kingdom. The former alone are commonly 
spoken of as food ; but the latter enter very largely into the consti- 
tution of the body, and must therefore be present in our food. 
With the exception of two articles — water and common salt — these 
substances enter the system only when blended with organic sub- 
stances. 

5. Water. — Water, from a physiological point of view, is the 
most important of all the articles of food. It is everywhere found 
in the body, even in the bones and the teeth. It has been com- 
puted that as large a proportion as two-thirds of the body is water. 
The teeth, the densest of the solids in the human system, contain 
ten per cent, of water. The muscles, tendons, and ligaments are 
more than half water ; for it is found that they lose more than half 
their weight when dried with moderate heat.. But it is in the fluids 
of the body that water is found most abundantly. It gives to them 
the power of holding a great variety of substances in solution, and 
is the great highway by which new supplies are conveyed to the 
point where they are required, and by which old particles of matter, 
that have served their uses, are brought to the outlets of the body 
to be thus removed from the system. {Read Notes 3 and 4. ) 

3. The Only Natural Drink. — "Water is the natural drink of man, as 
it is of all organized beings. It enters more largely into his composition than 
any other substance, giving liquidity to the blood, moisture to all the tissues," 
and serving as the great solvent of the body ; not less than two-thirds of its 
weight being of that element. It seems as if all organic beings were so much 
" organized water." "Soft water is mere wholesome than hard, though water 
moderately hard is not perceptibly injurious. When very hard, a part of the 
salts of lime can readily be precipitated by boiling. As a rule, spring and 
well-waters, if brought from deep fountains, are better and more wholesome 
than running streams. Well-water, in towns and cities, unless brought from 
a great depth, is wholly unfit for drinking and cooking. The immense quantity 



4. What classification? Define organic substances. Inorganic. Organic, how spoken 
of? The inorganic ? Water and salt? 

5. Water in physiology? Where found? Computation? Water in the teeth ? Muscles, 
tendons, and ligaments? How ascertained ? Water in the fluids of the body ? What is the 
advantage? 



68 THE CHEMISTRY OF FOOD. 

6. Man can remain a longer time without solid food than without 
water. He may be deprived of the former for ten or twelve hours 
without great suffering, but deprivation of water for the same length 
of time will produce both severe pain and great weakness. The 
food should contain not less than two parts of water to one of solid 
nutriment. Water constitutes the great bulk of all our drinks, and 
is also a large constituent of the meats, vegetables, and fruits which 
come upon the table. Fruits, especially, contain it in great abun- 
dance, and, in their proper season, furnish most agreeable and re- 
freshing supplies of the needed fluid. 

7. Common Salt. — Salt, or sodium chloride, as an article of food, 
is obtained chiefly from the mineral kingdom ; although plants con- 
tain it in small quantities, and it is also found in the tissues of 
nearly all animals used as food. In the human body it is an ingre- 
dient of all the solids and fluids. The importance of salt to animal 
life in general, is shown by the great appetite for it manifested by 
domestic animals, and also by the habitual resort of herds of wild 
beasts to the " salt-licks " or springs. In those parts of the world 

of organic matter which permeates every inch of the soil, for many feet in 
depth, precludes the possibility of water passing through it without being 
corrupted. River water, polluted by sewers, is as disgusting to the senses as 
it is destructive to health. The notion that impure water can be rendered 
more wholesome by icing it is an erroneous one. Ice-cold drinks in summer, 
while the body is heated, are capable of producing lifetime disease, and even 
instant death." — J. R. Black on the Ten Laws of Health. 

4. The Sustaining Power of Water.—" Water is the most reliable and 
grateful drink for man. Nature has many admixtures in the juices of fruits, 
but none so satisfying to excessive thirst as pure water. It will even prolong 
life when nutritious food is not taken, as we have a well-known instance, 
recorded by Dr. McNaughton, in the transactions of the Albany Institute of 
New York for 1836. The case was that of a man who lived upon water alone 
for fifty-three days. This he did while laboring under some delusion which 
impelled him to abstain from all ordinary nourishment — water alone could he 
be induced to partake of. His strength was tolerably well sustained during 
the first six weeks ; he was able, in fact, to go out of doors ; and even on the 
day of his death he was able to sit up in bed." — Dr. James Knight. 



6. Length of time man can do without food or water ? Give the comparison ? Bulk of 
drinks ? Constituent of meats, etc. ? Fruits ? 

7. Salt, how obtained ? Where found? In the human body ? Importance of salt ? What 
else can you state of the value of salt ? 



THE CHEMISTRY OF FOOD. 69 

where salt is obtained with difficulty, man places a very high price 
upon it. 

8. Experiments upon domestic animals show that the withdrawal 
of salt from their food, not only makes their hides rough and causes 
the hair to fall out, but also interferes with the proper digestion of 
food. If it be withheld persistently, they become entirely unable to 
appropriate nourishment, and die of starvation. {Read Note 5.) 

5. Of Salt.— 

" Salt-cellars ever should stand at the head 

Of dishes, wr.eresoe'er a table's spread. 

Salt will all poisons expurgate with haste, 

And to insipid things impart a taste. 

The richest food will be in great default 

Of taste, without a pinch of sav'ry salt. 

Yet of salt meats, the long-protracted use 

Will both our sight and manhood, too, reduce ; 

On tables salt should stand both first and last, 

Since, in its absence, there is no repast. " 

— The Code of the School of Sale-mum. 
"Animals will travel long distances to obtain salt. Men will barter gold 
for it ; indeed, among the Gallas and on the coast of Sierra Leone, brothers 
will sell their sisters, husbands their wives, and parents their children for 
salt. In the district of Accra, on the gold coast of Africa, a handful of salt is 
the most valuable thing upon earth after gold, and will purchase a slave or 
two. Mungo Park tells us that with the Mandingoes and Bambaras the use of 
salt is such a luxury that to say of a man, ' he flavors his food with salt,' it is 
to imply that he \ a rich ; and children will suck a piece of rock-salt as if it 
were sugar. No stronger mark of respect or affection can be shown in 
Muscovy, than the sending of salt from the tables of the rich to their poorer 
friends. In the book of Leviticus it is expressly commanded as one of the 
ordinances of Moses, that every oblation of meat upon the altar shall be 
seasoned with salt, without lacking ; and hence it is called the Salt of the 
Covenant of God. The Greeks and Romans also used salt in their sacrificial 
cakes ; and it is still used in the services of the Latin church — the 'parva 
mica,' or pinch of salt, being, in the ceremony of baptism, put into the child's 
mouth, while the priest says, ' Receive the salt of wisdom, and may it be a 
propitiation to thee for eternal life.' Everywhere, and almost always, indeed, 
it has been regarded as emblematical of wisdom, wit, and immortality. To 
taste a man's salt, was to be bound by the rites of hospitality ; and no oath 
was more solemn than that which was sworn upon bread and salt. To sprinkle 
the meat with salt was to drive away the devil ; and to this day, among the 

8. Experiments upon animals ? 



70 THE CHEMISTRY OF POOD. 

9. Salt is usually taken into the system in sufficient quantities in 
our food. Even the water we drink often has traces of it. The 
habitual use of much salt in cooking, or as a seasoning at the table, 
is not wise ; and while it may not lead to consumption, as some 
writers declare, it is a bad habit in itself, and leads to the desire for 
other and more injurious condiments. 

10. Lime. — This is the mineral substance which we have spoken of 
before as entering very largely into the composition of the bones. 
It is the important element which gives solidity and permanence to 
the framework upon which the body is built. Calcium tri- 
phosphate, or " bone-earth," is the chief ingredient of the bones and 
teeth, but is found in the cartilages and other parts of the body in 
smaller quantities. {Read Note 6.) 

superstitious, nothing is more unlucky than to spill the salt." — Letheby on 
Food. 

6. Phosphate of Lime and other Inorganic Substances. — "All 
food contains certain saline siibstances. If we burn a portion of the flesh of 
an}- animal, we may drive off the carbon, ox} 7 gen, hydrogen, and nitrogen, 
and ' ashes ' are left. These ashes are the saline and mineral (inorganic) con- 
stituents of the animal. They exist in the blood and tissues, and are as 
essential to the life of the animal as those other elements which were expelled 
by heat. Like the latter, the} 7 are constantly being used up and carried off 
from the body, and like them must be replaced by means of our food. Cook- 
ing, especially boiling, tends to dissolve away some of these salts, and care 
should be taken to supply them by means of uncooked food, as fresh vegetables 
and fruits ; milk also contains them. One of the most important of these in- 
organic substances is phosphate of lime, or ' bone-earth,' as it is called, from 
the fact that about forty per cent, of healthy bone is made up of it. "When 
it is deficient, the bones are soft and are liable to be bent by the actions of the 
muscles attached to them, and a permanent deformity may be the consequence. 
This form of lime is contained in wheat, barley, oats, and rye, and from these 
sources the chief supply of it is derived. These plants require phosphate of 
lime for their growth and the perfecting of their grains ; hence it is supplied 
artificially by the farmer. A diet deficient in substances yielding the phos- 
phate of lime is injurious to man, and should be avoided. Its presence in 
wheat-flour accounts in part for the fact that our ordinary loaf of bread makes 
so good a 'stiff of life.' and that it is, and has been, so widely used as an 
article of food by trie strongest and most vigorous races of mankind. " — Lan- 
kester's Manual, 

9. Salt, how taken into the system? Its use in cooking ? Consumption? 
10. Lime in the bones ? What does it impart? Chief ingredient of the bones and teeth ? 
Whe.e else found? 



THE CHEMISTRY OF FOOD. 71 

11. How does this substance find its way into the body 1 Meat, 
milk, and other articles obtained from the animal kingdom contain 
it, and it is abundantly stored away also in the grains from winch 
our bread is made — in wheat, rye, and Indian corn. In early life, 
while the body is growing, the supplies of this substance should be 
carefully provided. The evil effects of the deprivation of it are too 
often and painfully evident in the softening of the bones, and in the 
predisposition to curvature of the spine — deformities which are most 
deplorable and which continue through life. 

12. Iron. — This substance is probably the most abundant and 
widely diffused of the metals. It is found in most of the vegetables, 
and is a very important component of animal tissues. It enters into 
the composition of human blood in about one part per thousand. 
Ordinarily, the food conveys to the system enough iron for its use, 
but it must sometimes be introduced separately as a remedy, 
especially after great loss of blood, or after some wasting disease. 
Under its influence the blood seems to be rapidly restored, and a 
natural color of the lips and skin replaces the pallor caused by 
disease. # 

13. Other Inorganic Substances. — In addition to the substances 
mentioned, the mineral kingdom supplies compounds of soda, potash, 
and magnesia, which are essential for the use of the body. They 
occur in small quantities in the body, and enter it in combination 
with the various articles of diet. 

14. Organic Substances. — These substances are derived from the 
vegetable and animal creations. They comprise all those articles 
which are commonly spoken of as " food," and which are essential 
to sustain the body in life and strength. They are divided into 
three groups, namely : the Albuminoid substances, the Fats, and 
Sugars. 

15. The Albuminoids. — This class includes three important nutri- 
tive substances — (1) Albumen, which gives it its name ; (2) Fibrin, 



11. How does lime find its way into the body ? Early life ? Effect of its deprivation? 

12. Iron, its abundance and diffusion? Where found? What part of the blood is it ? How 
supplied to the system ? In case of loss of blood or wasting disease ? 

13. "Soda, potash, and magnesia? How do they occur? 

14. Organic substances, whence derived ? What do they comprise ? Groups? 

15. The Albuminoid class, includes what? These compounds constitute what? The food? 
Their imoortance ? Their properties ? 



72 THE CHEMISTRY OF FOOD. 

including gluten; and (3) Caseine. These compounds constitute a 
large part of the human body, and the food contains them in propor- 
tionally large quantities. Their importance is so great, and the 
system so promptly suffers from their absence, that they have been 
styled the "nutritious substances." The properties which they 
hold in common are, that they do not crystallize, and have a jelly- 
like form, except when heat is applied to them, when they harden, 
or coagulate. 

16. They likewise decompose, or putrefy, under the influence of 
warmth and moisture. Hence the decay of all dead animal tissues. 
Cold arrests this process. It is we\l known that milk, eggs, and the 
like, " keep " much longer in whiter than at other seasons. The 
bodies of elephants, caught in the ice many hundred years ago, are 
occasionally borne by the icebergs to the coast of Siberia, 
completely frozen, but preserved almost perfectly in form and 
limb. 

17. Albumen exists in milk, meat, the grains, and the juices of 
many plants ; but the purest form is obtained from the white of egg. 
When we consider that an egg is composed chiefly of albumen and 
water — namely, six parts in seven ; and when we also consider the 
numerous, diverse, and complex tissues — the muscles, bones, internal 
organs, bill, claws, and feathers — with which the chick is equipped 
on leaving his shell, we are impressed with the importance of 
these apparently simple constituents of the food and body. 
{Read Note 7.) 

7. "Weight and Health. — "The weight of the body is very generally 
assumed to be an infallible index or proof of the maintenance of a healthy con- 
dition of the body ; and that food which keeps up the weight has been 
regarded as satisfactory and nutritious. But this is not always a safe 
judgment, owing to the property in water from innutritious food to make good 
the loss of weight caused by the withdrawal of albumen and fat The weight 
may remain the same, while we are "losing flesh." Fat, also, may increase 
in badly nourished people, while the more essential element of albumen is 
diminishing ; . the fact being that the badly fed are not always lighter than 
those who are well nourished. And further, the feeling of satisfaction after 
eating is deceptive ; the Irish peasant who consumes ten pounds of potatoes in 



16. Decomposition? Effect of cold? Illustrations? Elephants? 

17. In what substances does albumen exist? What further is said of the egg? 



THE CHEMISTRY OF POOD. 73 

18. Fibrin is derived from meats,, and exists in the blood both of 
man and the lower animals. Gluten, or vegetable fibrin, resembles 
closely true fibrin, and is abundantly furnished in wheat and other 
grains from which flour is commonly made. Animal fibrin coagu- 
lates spontaneously when it is removed from the body, and thus 
causes the " clotting " of the blood. 

19. Caseine is the curdy ingredient of the milk, and a highly im- 
portant food-substance. Its coagulation in milk takes place not 
from heat, but by the addition of an acid, and also when milk be- 
comes sour from exposure to the air. It is commonly effected, 
however, by introducing a piece of rennet, a preparation made from 
a calf's stomach. The curds, or caseine, may then be separated from 
the lohey, and made into cheese, by pressing it sufficiently to drive 
off the water. 

20. The Fats or Oils. — This is the second group of organic 
foods. Those which are more solid are called fats; the more fluid 
ones are the oils. Oleaginous substances are supplied in both ani- 
mal and vegetable food ; but, from whatever source derived, they 
are chemically much alike. They are insoluble in water, and yet 
they unite readily with the watery fluids of the body, and are by 
them conveyed to its various parts for their nourishment. This is 
due to their property of " emulsifying ;" that is, they are held in 
suspension, in a finely divided state, in water. Ordinary milk is 
an example of an emulsion. We know that it contains fat, for 
butter is obtained from it ; and, under the microscope, the minute 
oil-globules may be distinctly seen. 

21. In our country and climate, and also in colder climates, fatty 
articles of food are principally derived from the animal creation, 
such as meat or flesh, milk and butter. But most of the bread- 
stuffs contain more or less fat or oil — Indian meal as much as nine 
parts in a hundred. 

a day feels quite satisfied, but is in reality badly nourished by his diet contain* 
ing three-fourths water." — Prof. Voit, of Munich. 



18. Fibrin, gluten, clotting of the blood? 

19. Caseine ? Its coagulation ? Effect of rennet ? Making of cheese ? 

20. What are the fats? The oils? How supplied ? How alike? Emulsifying? Exam- 
ple? How do we know it? 

21. Whence are fatty articles of food derived ? 



74 THE CHEMISTRY OF FOOD. 

22. Among persons living in cold climates, the appetite for 
oleaginous food is especially eager ; and they require large quanti- 
ties of it to enable them to resist the depressing influences of cold. 
Since vegetation is scanty and innutritious, and the waters of the 
frozen regions abound in animal life, they must rely wholly upon 
a diet derived from the latter source. The Esquimau consumes 
daily from ten to fifteen pounds of meat or blubber, a large propor- 
tion of which is fat. The Laplander will drink train-oil, and 
regards tallow-candles as a great delicacy. In hot climates, on the 
contrary, where flourish the olive and the palm, this kind of food 
may be obtained from vegetable sources in abundant quantities. 
{Read Notes 8 and 9.) 

8. The Necessity of Fat in the Food of Children. — " Children who 
dislike fat cause much anxiety to parents, for they are almost always thin, 
and, if not diseased, are not healthy. If care be not taken, they fall into a 
scrofulous condition, in which diseased joints, enlarged glands, sore eyes, and 
even consumption occur ; and every effort should be made to overcome this 
dislike. If attention be given to this matter of diet, there need be no anxiety 
about the possibility of increasing the quantity of food consumed ; whilst the 
neglect, the dislike, will probably increase until disease is produced. The 
chief period of growth — viz., from seven to sixteen years of age — \3 the most 
important in this respect, for a store of fat in the body is then essential. 
Those who are inclined to be fat usually like fat in food, and then it may be 
desirable to limit its use. Some who cannot eat it when hot like it when cold, 
and all should select that kind which they prefer. Those living in Russia and 
Lapland devour very large quantities — as seven pounds daily — and eat it even 
raw, while those dwelling in hot countries use very little. It produces more 
heat than any other kind of food. " — Edward Smith on Health. 

9. The Effect of Climate on the Appetite. — " Climate has an impor- 
tant influence on the quantity of food demanded by the system ; and every one 
has experienced in his own person a considerable difference at different seasons 
of the y ear. Travelers' accounts of the amount of food consumed by the na- 
tives of the frigid zone are almost incredible. They speak of men eating a 
hundred pounds of meat in a day ; and a Russian admiral, Saritcheff, men- 
tions an instance of a man who, in his presence, ate at a single meal a mess of 
boiled rice and butter weighing twenty-eight pounds. Although it is difficult 
to regard these statements with entire confidence, the general opinion is un- 
doubtedly well founded that the appetite is greater in cold than in warm 
climates. Dr. Hayes, the Arctic explorer, states, from his own observation, 



22. Appetite of persons in cold climates? What do they require? l*pon what must 
they rely? Why? The Esquimau? Laplander? Olive and palm? 



THE CHEMISTRY OF FOOD. 75 

23. The Sugars, op the Saccharine Substances. — These con- 
stitute the third and last group of the organic substances which are 
employed as food. This group embraces, in addition to the different 
kinds of Sugar, the varieties of starch and gum, from whatever 
source derived. The two substances last named do not, at first 
sight, present many points of similarity to sugar; but they closely 
resemble it in respect to their ultimate chemical composition, being 
made up of the same elements, in nearly the same proportions. 
And their office in the system is the same, since they are all changed 
into sugar by the processes of digestion. 

24. Sugar is chiefly of vegetable origin, the animal varieties 
being obtained from honey and milk. The most noticeable charac- 
teristic of this substance is its agreeable, sweet taste, which makes 
it everywhere a favorite article of food. But this quality of sweet- 
ness is not possessed by all the varieties of sugar in the same de- 
gree; that obtained from milk, for instance, has a comparatively 
feeble taste, but rather imparts a gritty feeling to the tongue. The 
other important properties of sugar are, its power to crystallize when 
evaporated from watery solutions, such as the juices of many plants ; 
a tendency to ferment, by which process alcohol is produced; and a 
ready solubility in water. This latter quality renders it very easy 
of digestion, and more so than any other of the saccharine group. 
It is computed that the annual production of sugar, in all parts of 
the world, is more than one million of tons. The kind of sugar 
that is in ordinary use, in this country, is prepared from the juice 
of the sugar-cane, which contains eighteen per cent, of sugar. In 
France it is manufactured from the beet-root, which holds about 

that the daily ration of the Esquimaux is from twelve to fifteen pounds of 
meat, about one-third of which is fat. He once saw an Esquimau consume 
ten pounds of walrus flesh and blubber at a single meal, which however lasted 
several hours, with the thermometer 60° or 70° below zero. Some members 
of his own party manifested a constant craving for fatty substances, and were 
in the habit of drinking the contents of the oil-kettle with evident relish. " — 
Flint's Physiology. 

23. Which are the third of the organic groups? What do they embrace ? Points of re- 
semblance ? 

24. Origin of the sugars ? Ordinary sugar? Beet-root? Maple-sugar? Grape-sugar? 
Cane-sugar ? 



76 



THE CHEMISTRY OF FOOD. 



nine per cent. ; the maple-tree of our climate yields a similar sugar. 
The sweet taste of fruits is due to the presence of grape-sugar : the 
white grains seen on raisins belong to this variety. Cane-sugar is 
more soluble than the latter, and has twice the sweetening power. 
{Read Note 10.) 
-4- 25. Starch. — This is the most widely distributed of the vegetable 
principles. It is tasteless, inodorous, and does not crystallize. It 
consists of minute rounded granules, which, under the microscope, 
reveal a somewhat uniform structure (Fig. 19). Starch will not 

dissolve in cold water, but in 
boiling water the small grains 
burst open, and may then be 
dissolved and digested. 

26. The breadstuff's — wheat, 
corn, and rye flours — are more 
than one -half starch. Eice, 
which is the " staff of life " to 
one-third of the human family, 
contains eighty per cent. Un- 
ripe fruits have much starch in 
them, which renders them in- 
digestible when eaten uncooked, 
for the grains of raw starch are 




Fig. 19. — Granules of Potato Starch Mag- 
nified. 



10. "Why too much Sugar is Injurious. — " Sugar is very wholesome, 
and, as I told you, we want some in our diet. But children will often eat too 
much sugax, just as they will eat too little fat. The harm it does them is — 
first, it is very apt to spoil the teeth ; second, it takes away the appetite for 
other food. If you are always eating sweet cakes and sugar-plums, you will 
not care for plain, nourishing diet. Now, what is best for us all is, to have 
good appetites for wholesome food ; it will do more to keep us in health all our 
lives than anything else ; and there is a great deal in getting the right habit." 
Candies are frequently adulterated with plaster-of-paris, chalk, and certain 
forms of earth, that are indigestible ; but worse than that, the coloring mat- 
ters and flavoring extracts that are used in the bright-tinted and fruity- 
flavored confectionery are absolute poisons in many instances, such as arsenic, 
copper, zinc, lead, prussic and sulphuric acid. — JBerner's Lessons on Health (in 
part). 

25. Starch, how widely distributed ? Its qualities ? Its constituents? Its solubility? 

26. How much starch in bread-stuffs ? In rice ? Unripe fruits ? Ripe fruits ? 



THE CHEMISTRY OF FOOD. 77 

but slightly acted upon within the body. But, under the potent 
chemistry of the sun's ray, this crude material is converted into 
sugar. Thus are the fruits prepared by the careful hand of Na- 
ture, so that when ripe they may be freely used without further 
preparation. 

27. Gum is commonly found in those articles which also contain 
starch, and has the same chemical composition as the latter, but is 
much less nutritious. In the East, gum-arabic and similar sub- 
stances are largely employed as food. Persons who travel by cara- 
van across vast, sandy deserts, find such substances well adapted to 
their wants, since they are not perishable, and are easily packed and 
carried. 

28. Stimulating Substances. — The three classes of food-princi- 
ples already considered — the Albuminoids, the Tats, and the Sugars 
— comprise all the more important organic ingredients of our food. 
There are, besides, a great variety of coloring and flavoring matters, 
that stimulate or increase the appetite for food by appealing to the 
eye and taste ; but they are not nutritious, and are quickly sepa- 
rated from the truly useful substances, and do not long remain in 
the body. Among these may be classed spices, flavors of fruits, 
tea, coffee, and vegetable acids. 

29. Necessity of a Regulated Diet. — A great variety of ex- 
periments have been tried, in order to test the relative value of the 
different nutritive principles. They have been practiced to some 
extent upon man, but chiefly upon those inferior animals which re- 
quire a similar diet to man. 

30. By this means it has been demonstrated that — first, when 
any one of these substances is eaten exclusively, the body is imper- 
fectly nourished, and life is shortened. Dogs fed exclusively upon 
either albumen, fat, or sugar, soon die of starvation. Second, a 
diet long deprived of either of these principles is a fertile cause of 
disease ; for example, on ship-board, where fresh vegetables are not 
dealt out for a long period, scurvy becomes prevalent among the 

27. Gum, where found? Its composition ? Gum Arabic? 

28. The three classes of food principles ? What besides ? What is said of them ? Name 
the articles not nutritious. 

29. What is said of experiments that have been tried ? 

30. What has been demonstrated in the first place? Example? Second demonstration ? 
Example'; Qive the illustration in relation to convertibility. 



78 THE CHEMISTRY OF FOOD. 

sailors. They are, however, to a certain extent mutually converti- 
ble, and thus the missing article is indirectly supplied. For in- 
stance, sugar changes to fat in the body ; and hence, as is well 
known, the "hands" on a sugar plantation grow fat during the 
sugar season, by partaking freely of the ripened juices of the cane. 
{Read Note II.) 

31. That is the best diet, therefore, which contains some of each 
of these principles, in due proportion ; and that is the worst which 
excludes the most of them. The cravings and experience of man 
had unerringly guided him to a correct regulation of his diet, long 
before the chemistry of food was understood ; so that his ordinary 
meals long ago combined these various principles, the necessity and 
value of which are now explained. {Read Notes 12 and 13.) 



11. The Effects of a Poor Diet.— "The food of the poor in olden 
times was poor and scanty ; so much so, in fact, that their powers of life were 
depressed ; and we believe this fact had much to do with the fearful mortality 
of the plague throughout Europe during the middle ages. The lower classes, 
especially those living in crowded cities, and subsisting on the scanty and 
monotonous diet that the historians of the period describe, were the principal 
sufferers. From 1296 to 1666, hundreds of thousands were carried off by the 
most fearfid pestilences the earth has ever known. Rye in France and oats in 
England were for generations the almost exclusive diet ; wheat was a luxury, 
which even the rich might only indulge in at Christmas. Oats were known 
in Germany 2,000 years ago, and were probably the original bread-grain for all 
Europe." — Dr. J. Knight. 

12. Variety in Diet and in its Preparation Beneficial. — "Every 
dietary should contain fresh vegetables. It is further necessary that certain 
articles belonging to the same class be varied from day to day, otherwise the 
appetite cloys. Beef should alternate with mutton, for example ; or variety 
should be secured by different modes of cooking the same article. Indeed, it is 
not too much to say that the art of cookery is a matter of national importance, 
not only because it renders food palatable, but because the more it is studied 
and practiced, the greater is the economy which may be effected. It is chiefly 
in this relation, that beverages, condiments, etc., become such valuable dietetic 
adjuncts." — Wilson's Hand-hook of Hygiene. 

13. Some Experiments as to Food. — "Magendie made numerous ex- 
periments on the inferior animals to test the value of different forms of nutri- 
ment. He showed that a diet exclusively composed of starch and sugar would 
not support life. So, too, dogs confined to white bread and water died with 
all the symptoms of starvation ; but on the military brown-bread animals lived 



THE CHEMISTRY OF FOOD. 79 

pretty well, as this article contains a greater variety of the alimentary princi- 
ples. Other experiments have given an account of geese limited to some one 
substance. All of them died — the animal led upon gum, on the sixteenth day ; 
that fed with sugar, on the twenty-first clay ; one fed with starch, on the 
twenty-fourth day ; and one fed with white of egg, on the twenty-sixth day. 
In 1769, before these experiments were performed, Dr. Stark, a young English 
physiologist, fell a victim at an early age to ill-judged experiments on himself 
as to the effects of different foods. He lived for forty-four days on bread and 
crater, for twenty-nine days on bread, sugar, and water, and for twenty-four 
lays on bread, water, and olive oil ; until finally, his constitution became 
broken, and he died from the effects of his experiments." — Flint's Physiology,, 



80 THE CHEMISTRY OF FOOD. 



QUESTIONS FOR TOPICAL REVIEW. 

PAGE 

1. What is understood by the term food? 65 

2. What can you state in relation to the source of food? 65 

3. What discriminations and selections are necessary ? 65, 66 

4. How can you tell the organic from the inorganic substances ? 67 

5. What relative position does water hold as an article of food ? , 67 

6. In what parts of the body is water found ? 67 

7 In what articles that we eat is it found? 6S 

& If you were required to go without water or solid food for a number of days, which 

would you prefer to have, and why ? 68 

9. What can you state of the importance of salt as an article of food ? 68 

10. How abundant is salt, and how does it find its way into the human system? 68 

11. What can you state of the importance of lime in the body ? In what does it occur ?. . 70 

12. What, of the importance of iron? , 71 

13. What further is stated of other inorganic substances ? 71 

14. What in relation to organic substances ?. .. 71 

15. What can you state in relation to the albuminoids ? 71, 72 

16. What, in relation to albumen ? 72 

17. What, in relation to caseine? 73 

18. In relation to the fats or oils, and how generally consumed ? 73 

19. What do we understand by the sugars or saccharine substances ? 73, 74 

20. State what you can of sugar— its origin and various qualities 75 

21. Of starch— its varieties and qualities 76 

22. Of the abundance of starch, and its importance as a food principle 76 

23. What is stated in relation to stimulating substances ?. 77 

24. Of the necessity for regulation in diet? -. 77 

25. What is considered the most healthful diet? 78 



Food and Drink. 

Necessity for Food — Waste and Repair — Hunger and Thirst — Amount of 
Food — Renovation of the Body — Mixed Diet — Milk — Eggs — Meat — Cooking 
— Vegetable Food — Bread — The Potato — Fruits — Purity of Water — Action 
of Water upon Lead — Coffee, Tea, and Chocolate — Effects of Alcohol. 

1. Necessity fop Food. — Activity is everywhere followed by 
waste. The engine uses up coal and water to produce motion, the 
stream wears away its bank, the growing corn-blade draws tribute 
from the soil. When the human body acts, and it is always in 
action during life, some of its particles are worn out and thrown off. 
This waste must constantly be repaired, or the body suffers. In this 
fact is seen the necessity for food. The particles, thus worn out, 
being henceforth useless, are removed from the body. Out food 
and drink are rapidly transformed into a new supply of living, 
useful material, to be in turn used up and replaced by a fresher 
supply. 

2. Waste and Repair. — In this way the healthful body, though 
always wasting, is always building up, and does not greatly change 
in size, form, or weight. At two periods of life the processes of 
waste and repair are not exactly balanced. In early life the process 
of building up is more active, and in consequence the form is 
plump and the stature increases. Repair now exceeds waste. On 
the other hand, when old age comes on, the wasting process is more 
active, the flesh and weight diminish, the skin falls in wrinkles, and 
the senses become dull. Only during the prime of life — from about 

1. What follows activity ? Examples? Necessity for food ? 

2. Give the theory in relation to waste and repair. 



82 FOOD AND DRINK. 

twenty to sixty years of age — is the balance exact between loss 
and gain. {Read Note i. ) 

3. Hunger and Thirst. — When the system is deprived of its 
supply of solid food during a longer time than usual, nature gives 
warning by the sensation of hunger, to repair the losses that have 
taken place. This sensation or pain appears to be located in 
the stomach, but it is really a distress of the system at large. Let 
a sufficient quantity of nourishment be introduced into the system 
in any other way than by the mouth, and it will appease hunger 
just as certainly as when taken in the usual manner. 

4. The feeling of thirst, in like manner, is evidence that the 
system is suffering from the want of water. The apparent seat of 
the distress of thirst is in the throat ; but the injection of water into 
the blood-vessels is found to quench thirst, and by the immersion of 
the body in water, the skin will absorb sufficient to satisfy the de- 
mands of the system. The length of time that man can exist 
without food or drink is estimated to be about seven days. If watei 
alone be supplied, life will last much longer — there being cases 

1. The "Waste of the Body.—" In the physical life of man there is 
scarcely such a thing as rest — the numberless organs and tissues which com- 
pose his frame are undergoing perpetual change, and in the exercise of the 
function of each some part of it is destroyed. Thus, we cannot think, feel or 
move without wasting some proportion, great or small, according to the energy 
of the act, of the apparatuses concerned — such as brain, nerve or muscles. 
Now this waste-product cannot remain in its original situation, where it would 
not only be useless dross, but also obstructive and injurious. Such old 
material is being daily removed from our bodies to the average amount of three 
or more pounds ; and that an equal quantity of new shall take its place is the 
first principle of alimentation. To express it in commercial language, the in- 
come must be equal to the expenditure ; and in each of us the amount of this 
exchange must in a lifetime reach many tons. This tissue-change is so com- 
plete, that not a particle of our present body will be ours a short time hence ; 
and we will be, as I have lately seen it phrased, like the knife which, after 
having had several new blades, and at least one new handle, was still the same 
old knife to its owner. "We are, in fact, constantly * moulting. ' " — Mapother's 
Lectures on Public Health. 



3. System deprived of food ? Warning ? What is the pain ? How proved ? 

4. Feeling of thirst ? Seat of the pain ? How proved? Time a person can exist without 
food? * -*..... v 



FOOD AND DRINK. 83 

recorded where men have lived twenty days and over without 
taking any solid food. {Read Note 2. ) 

5. Quantity of Food. — The quantity of food required varies 
greatly, according to the individual and his mode of life. The 
young, and others who lead active lives, or who live in the open air, 
require more food than the old, the inactive, or the sedentary. 
Those who live in cold regions require more than the inhabitants of 
hot climates. Habit, also, has much to do with the quantity of 
food required. Some habitually eat and drink more than they 
actually need, while a few eat less than they should. 

6. The average daily quantity of food and drink for a healthy 
man of active habits is estimated at six pounds. This amount may 
be divided in about the following proportions : the mineral kingdom 
furnishes three and one-half pounds, including water and salt ; the 
vegetable kingdom, one and one-half pounds, including bread, 
vegetables, and fruits ; the animal kingdom, one pound, comprising 
meat, eggs, butter, and the like. This quantity is about one 
twenty-fourth the weight of the body, as it is generally computed ; 
the average weight of an adult man being placed at 140 pounds. A 

2. Hunger and Thirst. — " We none of us object to a sharp-set appetite ; 
that is by no means unpleasant, especially when there is food at hand ; but if 
this is not the case, it soon becomes a craving passion — a strong impelling 
power. The cravings of hunger have done much for this world ; ' look where 
we may, we see it as the motive power which sets the vast array of human 
machinery in action. ' Hunger is also the incentive which directs our atten- 
tion to the system's need for food, and if it be sharp enough the most 
loathsome substances are greedily devoured. By it has man, and civilized 
man, too, been driven to feed upon the putrid corpse of his comrade. Hunger 
is one of the great forces in action in the preservation of the life of the indi- 
vidual ; and the fear of it is one of the strongest incentives to action. But the 
pangs of hunger are tolerable in comparison with the tortures of raging thirst. 
In fact, so terrible are the latter that they form one of the cruelest tortures 
which man can inflict on man ; so cruel a torture, indeed, that it has rarely 
been used, except in cases of bitter personal animosity, by others than brutal 
Eastern tyrants, or bigots under the influence of religious fanaticism." — 
Fothergill on the Maintenance of Health. 



5. Amount of food required ? The young and others ? Those living in hot and cold climates ? 
Habits? 

6. Quantity of food daily ? How divided ? Compare with the weight of the body. 



84 



FOOD AND DRINK. 



man, therefore, consumes an amount of solid and liquid nutriment 
every twenty-four days equal in weight to that of his body, a cor- 
responding amount being excreted^ or removed from the system in 
the same time. {Read Notes 3 and 4. ) 

3. A Lifetime Allowance of Food. — "M. Soyer, in his 'Modern 
Housewife,' makes a calculation as to how much food an epicure of 70 years of 
age has consumed. This imaginary epicure, who is supposed to he a wealthy 
personage, is placed by him on Primrose Hill at ten years old and told to look 
around him at the vast assemblage of animals and other objects he will in the 
course of a lifetime send down his throat — the sight of which is, of course, de- 
scribed as appalling. Among the other things, he is to devour 30 oxen, 200 
sheep, 100 calves, 200 lambs, 50 pigs, 1,200 fowls, 300 turkeys, 263 pigeons, 
120 turbot, 140 salmon, 30,000 oysters, 5,745 lbs. of vegetables, 243f lbs. of 
butter, 24,000 eggs, and 4-| tons of bread, besides fruits, sweetmeats, etc., 
and 49 hogsheads of wine, 548 gals, of spirits, and about 3,000 gals, of tea and 
coffee. This is a mere outline of what we are told is destined to be consumed. 
To show there is no exaggeration, Soyer assures us that he has from experience 
made up a scale of food for the day for a period of 60 years, and it amounts to 
33f tons of meat, farinaceous food, and vegetables, etc." — Journal of 
Chemistry. 

4. A Daily Ration for an Adult Man. — " TTe may arrive at something 
like an average daily diet by taking the case of the man in good health, 
weighing 154 lbs., and measuring 5 feet 8 inches in height. Simply to main- 
tain his body, without loss or gain in weight, his ration of food should not 
contain less, during 24 hours, than the following proportions and quantities of 
the main ingredients : 



THE AVERAGE DAILY DIET FOR AX ADULT. 



'food substances. 


PER CESTTEM. 


WEIGHT. 


Water 


81.5 
3.9 
10.6 
3.0 
.7 
.3 


lbs. oz. grs 

5 8 320 

4 110 

11 178 

3 337 

325 

170 




Fat 




Phosphates, potash, salts, etc 






100. 


6 13 128 



" Water, it will be remembered, enters into the composition of every article 
of food as well as in the liquids we drink. In reality, the weight of the dry 



t-. 



POOD AND DRINK. 85 

7. Renovation of the Body. — By this process, so far as weight is 
concerned, the body might be renewed every twenty-four days ; but 
these pounds of food are not all real nutriment. A considerable 
portion of that which we eat is innutritious, and though useful in 
various ways, is not destined to repair the losses of the system. An 
opinion has prevailed that the body is renewed throughout once in 
seven years ; how correct this may be, it is not easy to decide, but 
probably the renovation of the body takes place in a much shorter 
period. Some parts are very frequently renewed, the nutritive 
fluids changing more or less completely several times during the 
day. The muscles, and other parts in frequent exercise, change 
often during a year ; the bones not so often, and the enamel of the 
teeth probably never changes after being once fully formed. 
{Read Note 5.) 

8. Mixed Diet. — The habits of different nations in respect to diet 
exhibit the widest and strangest diversity. The civilized cook their 
food, while savages often eat it in a raw state. Some prefer it when 
fresh; others allow it to remain until it has become tainted with 
decay. Those dwelling in the far north subsist almost wholly on 



food we take will exceed that given above ; chiefly for the reason that they do 
not come to us pure and unmixed with fibrous material and gelatine, whose 
use in nourishing the body is limited and uncertain." — Kensington Museum 
Hand-Book on Food. 

5. The Renewal of the Body. — "To meet these constant chemical 
changes, material is taken in, in the form of food and drink, which is being 
constantly assimilated, and so nutrition and repair are conducted. The rapid- 
ity with which these changes are carried on is much greater than is usually 
supposed. Paley, in his ' Natural Theology,' states that seven years are 
requisite for the perfect renewal of the body ; and this statement, owing partly 
to the mysticism associated with the number 7, is generally accepted and 
believed. The time really is rather months than years ; but it is absurd to fix 
a time which must necessarily vary in different individuals, being much less in 
the infant than in the aged, in the active than the indolent ; widely different, 
too, in various tissues, from the epithelium lining of the glands of the stomach, 
renewed several times in each act of digestion, to the enamel of the tooth, 
which is probably never renewed during a lifetime." 



7. How often, then, might the body be renewed ? Why is it not? Opinion? How correct? 
What further is stated? 

8. Habits of nations? Give the different cases. 



86 FOOD AND DRINK. 

animal food, while those living in hot climates have bountiful 
supplies of delicious fruits with which to satisfy all their bodily 
wants. One race subsists upon the banana, another upon the 
blubber of seals. In temperate climates, a diet composed partly 
of vegetable and partly of animal food is preferred. {Read Note 6.) 

9. The important point to consider is, however, not one of origin, 
but whether the chemical principles (mentioned in the last chapter) 
enter into the composition of the diet. A purely vegetable diet may 
be selected which would contain all the principles necessary to 
sustain life. It is recorded of Louis Cornaro, a Venetian noble, that 
he supported himself comfortably for fifty-eight years on a daily 
allowance of twelve ounces of vegetable food, and about a pint of light 
wine. On the other hand, the food of John the Baptist, consisting of 
" locusts and wild honey," is an example of the sustaining power of 
a diet chiefly animal in its origin. 

10. In our climate, those who lead active lives crave an allowance 
of animal food ; and it has been found by experience that with it 
they can accomplish more work and are less subject to fatigue, than 
without it. Among nations where an exclusively vegetable diet 
is employed, indigestion is a disorder especially prevalent. 
{Read Note'].) 

6. Different Effects of Animal and Vegetable Food. — "Raw meat 
gives fierceness to animals, and would do the same to man. This is so true 
that the English, who eat their meat underdone, seem to partake of this fierce- 
ness more or less, as shown in pride, hatred, and contempt of other nations." — 
De La Mettrie. 

" The camivora are, in general, stronger, bolder, and more pugnacious than 
the herbivora on which they prey ; in like manner, those nations who live on 
vegetable food differ in disposition from such as live on flesh. *' — Liebig. 

7. A Mixed Diet affords the best Results. — " The mixed diet to 
which the inclination of man in temperate climates seems usually to lead him, 
when circumstances allow that inclination to develop itself freely, appears to 
be fully conformable to the construction of his dental and digestive apparatus, 
as well as to his instinctive cravings. And whilst on the one hand it may be 
freely conceded to the advocates of ' vegetarianism,' that a well-selected 
vegetable diet is capable of producing, in the greatest number of individuals, 
the highest physical development of which they are capable, it may, on the 



9. The point to consider? Vegetable diet ? Louis Cornaro ? John the Baptist? 
10. What has been found in our climate? Exclusive vegetable diet? 



FOOD AND DRINK. 87 

It. The necessity for occasionally changing or varying the diet, is 
seen in the fact that no single article comprises all the necessary 
principles of food, and that the continuous use of any one diet, 
whether salt or fresh, is followed by defective nutrition and disease. 
There is one exception to this rule : in infancy, milk alone is best 
calculated to support life ; for then the digestive powers are incom- 
pletely developed, and the food must be presented in the simplest 
form possible. It should also be remembered that too rich diet is 
injurious, just as truly as one that is inadequate. When the food of 
horses is too nutritious, instinct leads them to gnaw the wood-work 
of their mangers. 

12. Different Articles of Diet— Milk.— Milk is the earliest 
nutriment of the human race, and in the selection and arrangement 
of its constituents, may be regarded as a model food, no other single 
article being capable of sustaining life so long. Cows' milk holds 
caseine, one of the albuminoids, about five parts in one hundred ; 
a fatty principle, when separated, known as butter, about four parts ; 
sugar of milk four parts ; water and salts eighty-seven parts. The 
caseine and fatty substance are far more digestible in milk than 
after they have been separated from it in the form of cheese and 
butter. 

13. Since milk, in itself, is so rich an article of food, the use of it 
as a beverage is unwise, unless the quantity of the other articles 
consumed be reduced at the same time. The milk sold in cities is 
apt to be diluted with water. The way to detect the cheat is by 
testing the specific gravity of the article. Good milk is about 1030 ; 

other hand, be affirmed with equal certainty, that the substitution of a 
moderate proportion of animal flesh is in no way injurious ; but, so far as our 
evidence at present extends, this seems rather to favor the highest mental de- 
velopment. And we can scarcely avoid the conclusion that the Creator, by 
conferring on a man a remarkable range of choice, intended to qualify him for 
subsisting on those articles of diet, whether animal or vegetable, which he 
finds most suitable to his tastes and wants." — W. B. Carpenter on the Prin- 
ciples of Physiology. 

11. Necessity for change in diet ? Continuous use of the same diet ? Exception? Why? 
Too rich diet ? Horses ? 

12. Milk as a model food ? Cows' milk ? The constituents when separated ? 

13. Milk as a beverage ? Milk sold in cities ? How to detect the cheat ? 



88 FOOD AND DRINK. 

skimmed milk, 1035 ; but milk diluted one-fifth is 1024. An in- 
strument called the lactometer is also used, by which the amount of 
cream present is ascertained. 

14. Eggs. — The egg is about two-thirds water, the rest is pure- 
albumen and fat in nearly equal portions. The fat is in the 
yolk, and gives it its yellow color. Eggs contain none of the 
sugar principles, and should be eaten with bread or vegetables 
that contain them. Soft-boiled eggs are more wholesome than 
those which are hard-boiled or fried, as the latter require longer 
time to digest. 

15. Meats. — The meats, so called, are derived from the musculai 
parts of various animals. They are most important articles of food 
for adults, inasmuch as they are richly stored with albuminoid sub- 
stances and contain more or less fat. Such food is very nourishing, 
and easily digested if eaten when fresh, — veal and pork being- 
exceptions. The flesh of young animals is more tender and, in 
general, more digestible than that of older ones. All meat is more 
tough immediately after the killing of the animal, but improves by 
being kept a certain length of time. 

16. Some persons prefer flesh that has begun to show signs of 
decomposition, or is unmistakably putrid. By some, venison is not- 
considered to have its proper flavor until it is tainted. In England, 
people prefer mutton that is in a similar condition, just as on the 
continent of Europe many delight in cheese that is in a state of de- 
composition. In certain less civilized countries, flesh is not only 
eaten uncooked, but in a mouldy, rotten condition. The use of 
such food is not always immediately injurious, but it predisposes to 
certain diseases, as indigestion and fevers. {Read Note 8.) 

8. A Summary Concerning Diet. — " The food on which the man who 
would be healthy should live, should be selected so as to insure a variety 
without excess. Animal food should not be taken oftener than twice daily. 
The amount of animal and vegetable food combined should not exceed 30 
ounces in the 24 hours; and for the majority of persons an average of 24 
ounces of mixed solid food, a third only of which should be animal, is suffi- 



14. Composition of eggs? Yolk? How should eggs be eaten? Why? How boiled? 
Why? 

15. Meats, whence derived ? Why important? Flesh of young animals ? 

16. Preference of persons? Venison? Mutton? Cheese? Uncooked flesh ? 



FOOD AND DRINK. 89 

17. Cold is one means of preserving meat from decay. In trie 
markets of northern Russia, the frozen carcases of animals stand 
exposed for sale in the winter air for a considerable time, and are 
sawed in pieces, like sticks of wood, as the purchases are made — ■ 
such meat, when thawed, being entirely fit for food. Beef and 
pork are preserved by salting down in brine, and in this condition 
may be carried on long voyages, or kept for future use. Salted 
meat is not as nutritious as fresh, since the brine absorbs its rich 
juices and hardens its fibres. Long continued use of salt meats, 
without fresh vegetables, gives rise to the disease called scurvy, 
formerly very prevalent on ship-board and in prisons, but now 
scarcely known. 

18. Cooking. — The preparation of food by the agency of fire is of 
almost universal practice, even among the rudest nations. The ob- 
ject of cooking is to render food more easy of digestion by softening 
it, to develop its flavor, and to raise its temperature more nearly to 
that of the body. A few articles of flesh-food are eaten uncooked 
in civilized lands, the oyster being an instance. Raw meat is occa- 
sionally eaten by invalids with weak digestive powers, and by men 
training for athletic contests. 

19. In boiling meat, the water in which it is placed tends to dis- 
solve its nutrient juices. In fact, the cooking may be so conducted 
as to rob the meat of its nourishment, its tenderness, and even of 
its flavor. The proper method, in order to preserve or promote 
these qualities, is to place the meat in boiling water, which, after a 
few minutes, should be reduced in temperature. In this way the 
intense heat, at first, coagulates the exterior layers of albumen, 
and imprisons the delicate juices ; after that, moderate heat best 

cient. All animal foods should be eaten while they are fresh, and after they 
have been well cooked. The habit of eating underdone flesh is an almost cer- 
tain cause of parasitic disease. The amount of fluid taken, in any form, 
should not exceed the average of 24 ounces daily. Water is the only natural 
beverage. " — Dr. B. W. Richardson, The Diseases of Modern Life. 

17. Cold as a preserver? Meat in Russia ? Beef and pork, how preserved ? Salted meat 
as food? Scurvy? 

18. The antiquity of the custom of cooking food? Object of cooking? The oyster? 
Raw meat as an occasional food ? 

19. Effect of boiling meat? How may the cooking be done? The proper method? 
Effect? Making of soup? 



90 FOOD AND DRINK. 

softens it throughout. When soup is to be made an opposite 
course should be pursued; for then the object is to extract the 
juices and reject the fibre. Meat, for such purpose, should be cut 
in small pieces and put into cold water, which should then be gradu- 
ally raised to boiling heat. {Read Note 9. ) 

20. Roasting is probably the best method of cooking meat, 
especially "joints" or large pieces, as by this process the meat is 
cooked in its own juices. Roasting should begin with intense heat, 
and be continued at a moderate temperature, in order to prevent 
the drying out of the nutritious juices, as by this process an outer 
coating or crust of coagulated albumen is formed. During this 
process the meat loses one-fourth of its weight, but the loss is 
almost wholly water, evaporated by the heat. Too intense or pro- 
longed heat will dry the meat, or burn it. Frying is the worst 



9. Cooking Paves the "Way for Easy Digestion. — The objects to 
be obtained by cooking meat are : 1. To coagulate the albumen and blood of 
the tissues, so as to render the meat agreeable to the sight. 2. To develop 
flavors, and to make the tissue crisp, as well as tender, and therefore more 
easy of mastication and digestion. 3. To secure a certain temperature, and 
thus to be a means of conveying warmth to the system. 4. To kill parasites 
in the tissues of the meat. 

The action of heat should not be continued after these objects are accom- 
plished, as the meat will thereby be rendered indigestible. If a piece of meat 
be placed in water which is briskl} r boiling, a crust, so to speak, is formed by 
the rapid coagulation of the albumen upon and near the surface ; so that the 
juice of the meat cannot escape, nor the water penetrate its interior. If, on 
the other hand, the meat be put in cold water, and slowly heated, the albumen 
is gradually dissolved, and exudes into the water, making good soup, but leav- 
ing the meat poor and tasteless. Even in roasting meat the heat must be 
strongest at first, and it may then be much reduced. The juice which, as in 
boiling, flows out, evaporates, in careful roasting, from the surface of the 
meat, and gives to it the dark brown color, the lustre, and the strong aromatic 
taste of roast meat. All baked and roasted fatty foods are apt to disagree with 
delicate stomachs ; and it is often remarked that, although bread and butter, 
boiled puddings, boiled fish, or boiled poultry can be eaten freely without dis- 
comfort, yet toast and butter, or meat pies and pastry, or fried fish, or roasted 
fowl will disagree with the stomach. — Letheby on Food. 



20. Roasting? How should it be done? Give the philosophy of the process. Frying? 



FOOD AND DRINK. 91 

possible method, as the heated fat, by penetrating the meat, or 
other article placed in it, dries and hardens it, and thus renders 
it indigestible. 
~i — 21. Trichina. — It should be remembered that ham, sausages, 
and other forms of pork, should never be eaten in a raw or imper- 
fectly cooked condition. The muscle of the pig is often infested 
by a minute animal parasite, or worm, called trichina spiralis. 
This worm may be introduced alive, in pork food, into the human 
body, where it multiplies with great rapidity, and gives rise to a 
painful and serious disease. This disease has been prevalent in 
Germany, and cases of it occur from time to time in this country. 

22. Fish. — The part of fish that is eaten is the muscle, just as 
in the case of the meats and poultry. It closely resembles flesh in 
its composition, but is more watery. Some varieties are very easy 
of digestion, such as salmon, trout, and cod; others are quite indi- 
gestible, especially lobsters, clams, and shell-fish generally. A diet 
in which fish enters as the chief article, is ill adapted to strengthen 
mind or body, while its continued use is said to be the fertile 
source of nearly every form of disease of the skin. Some persons 
are so constituted that they can eat no kind of fish without 
experiencing unpleasant results. 

23. Vegetable Food. — The list of vegetable articles of diet is a 
very long one, including the grains from which our breadstuff's are 
made, the vegetables from the garden, and the fruits. All the 
products of the vegetable kingdom are not alike useful. Some are 
positively hurtful; indeed the most virulent poisons, as strychnia 
and prussic acid, are obtained from certain vegetables. Again, of 
such articles as have been found good for food, some are more 
nourishing than others ; some require very little preparation for 
use, while others are hard and indigestible, and can only be used 
after undergoing many preparatory processes. Great care must 
therefore be exercised, and many experiments made, before Ave can 
arrive at a complete knowledge in reference to these articles of diet. 



21. What is " Trichina ? " How guarded against? 

22. What part of fish is eaten? What does it resemble? Fish as food for digestion? 
Fish as a diet? 

23. List of vegetable articles? Usefulness of the different vegetables? Strychnia t 
What further is said in relation to the nourishing and other qualities of vegetables ? 



92 FOOD AND DRINK. 

Tea, coffee, and other substances from which drinks are made are of 
vegetable origin. 

24. Bread. — Wheat is the principal and most valuable kind of 
grain for the service of man. Bread made from wheat-flour ha& 
been in use for many hundreds of years, and on this account, as 
well as because of its highly nourishing properties, has been aptly 
called "the staff of life." We never become tired of good bread as 
an article of daily food. The white kinds of flour contain more 
starch and less gluten than the darker, and are therefore less nutri- 
tious. The hard-grain wheat yields the best flour. In grinding 
wheat, the chaff or bran is separated by a process called "bolting." 
Unbolted flour is used for making brown or Graham bread. 
{Read Note 10. ) 

25. The form of bread most easily digested is that which ha& 
been " leavened," or rendered porous by the use of yeast, or by some 

10. Bread. — "The health and power of a nation, as of an army, depend 
greatly on its food. The quality of bread in any nation, community, or family 
is a pretty good measure of its civilization. Xo one can entirely dispense with 
it. Good or bad, in some form it must be had. So it is, and has been from 
the earliest records of the race, and so it will doubtless continue. Leavened 
or fermented bread is as old as the time of Moses, and its value has been fully 
tested. Whatever be the precise action of the leaven, it transforms the grain 
by partial decomposition of its original elements, and leaves as its resultant 
what all men in all ages have approved. Is the art of making good, honest, 
leavened, Bible bread lost in Massachusetts, as some of our friends declare ? 
Baker's bread is almost universally adulterated. Bread hastily made in fam- 
ilies is mixed in a variety of ways, with a variety of chemicals, and is gener- 
ally imperfectly cooked. Very often the elements of wheat and fat which the 
body demands (a wise and witty clergyman of the last generation used to say, 
' bread is the staff of life, but bread and butter is a gold-headed cane ') are 
furnished in underdone pastry, made from flour and hog's lard. Any 
family who will take the pains can have good bread. It involves not more 
than ordinary skill and judgment. It is to be found on the continent of 
Europe, on all the great lines of travel, and is as common among the people of 
France and Germany as it is rare with us. The materials for an honest, 
wholesome loaf are simple and not expensive. The value of time and labor 
required for kneading the dough are the only difficulties, and these we would 
not undervalue ; they are in many families very serious, and not easily over- 
come. " — Derby on the Food of Massachusetts. 

24. Wheat? "Staff of life? White flour? Hard-grain wheats? Bolting? Graham 
bread ? 

1L Leavened bread? Unleavened? Hot bread? 



FOOD AND DRINK. 93 

similar method. Unleavened bread requires much more mastica- 
tion. Hot bread is unwholesome, because it is not firm enough to 
be thoroughly masticated, but is converted into a pasty, heavy mass, 
that is not easily digested. 

26. Wheaten bread contains nearly every principle requisite for 
sustaining life, except fat. This is commonly added in other 
articles of diet, especially in butter, — "bread and butter," conse- 
quently, forming an almost perfect article of food. The following 
experiment is recorded : "A dog eating ad libitum of white bread, 
made of pure wheat, and freely supplied with water, did not live 
beyond fifty days. He died at the end of that time with all the 
signs of gradual exhaustion." Death took place, not because there 
was anything hurtful in the bread, but because of the absence of 
one or more of the food principles. 

27. The Potato. — The common or Irish potato is the vegetable 
most extensively used in this country and Great Britain. Among 
the poorer classes in Ireland it is the main article of food. While 
it is not so rich in nutritious substances as many others, it has some 
very useful qualities. It keeps well from season to season, and 
men do not weary of its continuous use. It is more than two- 
thirds water, the rest being chiefly starch, with a little albumen. 

28. The sweet potato differs from the white or common in con- 
taining more water and a small proportion of sugar. The common 
potato and the tomato belong to the same botanical order as the 
" nightshades," but do not possess their poisonous qualities, unless 
we except potatoes that are in the process of germination or sprout- 
ing, when they are found injurious as food. 

29. Fruits. — These are produced, in this country, in great 
abundance, and are remarkable alike for their variety and delicious 
flavor; consequently they are consumed in large quantities, espe- 
cially during the warmer months. The moderate use of ripe 
fruits, in their season, is beneficial, because they offer a pleasant 
substitute for the more concentrated diet that is used in cold 



26. Wheaten bread ? Bread and butter ? Experiment on the dog ? 

27. State what is said of the Irish potato? 

28. Sweet potato? Nightshades? Potatoes when germinating? 

29. Fruits? Use of ripe fruit? Nutriment they contain? Starch in unripe fruits? 
Ccoking of unripe fruits? 



94 FOOD AivD DRINK. 

weather. The amount of solid nutriment they contain is, however, 
small. The percentage of water in cherries is seventy-five, in 
grapes eighty-one, in apples eighty-two. Unripe fruits contain 
starch, which, during the process of ripening, is converted into 
sugar. Such fruits are indigestible, and should be avoided ; cook- 
ing, however, in part removes the objections to them. 

30. Pure Water. — It is important that the water we drink and 
use in the preparation of food should be pure. It should be clear 
and colorless, with little or no taste or smell, and free from any 
great amount of foreign ingredients. Chemically pure water does 
not occur in nature; it is obtained only by the condensation of 
steam, carefully conducted, and is not as agreeable for drinking 
purposes as the water furnished by springs and streams. Rain- 
water is the purest occurring in nature; but even this contains 
certain impurities, especially the portion which falls in the early 
part of a shower ; for in its descent from the clouds, the particles 
floating in the air are caught by the falling drops. 

31. Water from springs and wells always contains more or less 
foreign matter of mineral origin. This imparts to the drink its 
pleasant taste — the sparkle, or "life," coming from the gases ab- 
sorbed by the water during its passage under ground The ordi- 
nary supply of cities is from some pure stream or pond, conveyed 
from a distance through pipes, the limpid fluid containing generally 
only a small amount of impurity. Croton water, the supply of 
New York City, is very pure, and contains only four and a half 
grains to a gallon ; the Ridgewood water, of Brooklyn, holds even 
less foreign matter. 

32. Drinking-water may contain as large a proportion as sixty to 
seventy grains per gallon of impurity, but a much larger quantity 
renders it unwholesome. The mineral spring waters, used popu- 
larly as medicines, are highly charged with mineral substances. 
Some of them, such as the waters at Saratoga, contain three hun- 
dred grains and more to the gallon. (Read Note n.) 

11. Impure Water Spreads Disease. — "In the year 1867, three 

30. How should drinking-water be as regards color and smell ? Chemically pure water ? 
How obtained ? Agreeableness of perfectly pure water 1 

31. Spring and well water ? Whence the sparkle, or life ? The water supply of cities ? 
Croton water ? Ridgewood ? 

32. Impurities in drinking-water ? Mineral springs ? 



FOOD AND DRINK. 95 

33. Action of Water upon Lead. — The danger of using watei 
that has been in contact with certain metals is well known. Lead 
is one of the most readily soluble, and probably the most poisonous 
of these substances in common use. When pure water and an 
untarnished surface of lead come in contact, the water gradually 
corrodes the metal, and soon holds an appreciable quantity of it in 
solution. When this takes place the water becomes highly inju- 
rious ; the purer the water, and the more recent the use of the 
metal, the greater will be the danger. {Read N^e 12.) 



millions of pilgrims, of whom a handful had come from a cholera district, 
assembled at Hurdwar, a few miles from the spot where the Ganges escapes 
from the Himalayas. On the 12th of April the three millions resolved to 
bathe and drink. ' The bathing-place of the pilgrims was a space 650 feet 
long by 30 feet wide, shut off from the rest of the Ganges by rails. Into this 
long and narrow inclosure pilgrims from all part° of the encampment crowded 
as closely as possible from early morn to sunset ; the water within this space, 
during the whole time, was thick and dirty — partly from the ashes of the 
dead, brought by surviving relatives to be deposited in the water of their river 
god, and partly from the washing of the clothes and bodies of the bathers. 
Now, pilgrims at the bathing ghaut, after entering the stream, dip themselves 
under the water three times or more, and then drink of the holy water, whilst 
saying their prayer. The drinking of the water is never omitted ; and when 
two or more members of a family bathe together, each from his own hand 
gives to the other water to drink. On the evening of the next day, the 13th 
of April, eight cases of cholera were admitted into one of the hospitals at 
Hurdwar. By the 15th, the whole of this vast concourse of pilgrims had dis- 
persed,' carrying the cholera in every direction over India; it attacked the 
British troops along the various routes, it passed the northern frontier, got 
into Persia, and so on into Europe, where it will work its wicked will for some 
time to come. That is a sample of the mischief water can do in the way of 
spreading disease." — London Medical Press. 

12. Lead in Drinking-Water. — " The danger of using lead for pipes or 
cisterns is now well known, the case of the late royal family of France, at 
Claremont, having made the matter notorious. In this case there was one- 
tenth of a grain in the gallon, and one-third of the persons who drank the 
water were affected. But even one one-hundredth of a grain per gallon has 
produced palsy in those who drank this impurity habitually. It is remarkable 
that the Thames water will at one time dissolve lead, and not at another."— 
Ma-pother's Health Lectures. 

33. What is stated of the action of water upon lea4? 



96 FOOD AND DRINK. 

34. In cities, lead pipes are commonly used to convey water 
through the houses; lead being also used in the construction of 
roofs, cisterns, and vessels for keeping water and other liquids. 
After articles made of lead have been in use several months, the 
danger of lead-poisoning diminishes. An insoluble coating of the 
sulphate of lead forms upon the exposed surface, thus protecting it 
from further corrosion. It is, however, a wise precaution, at all 
times, to reject the water or other fluid that has been in contact 
with leaden vessels over night, or for a number of hours. Allow 
the water in pipes to run freely before using. 

35. Coffee. — This is an important addition to diet, and, if mod- 
erately used, is beneficial to persons of adult age. As commonly 
employed, it consists of an infusion in boiling water of the roasted 
and ground berry. The water extracts certain flavoring and color- 
ing matters, but that which gives it its peculiar stimulant qualities 
is the alkaloid caffeine. With most persons its action is that of a 
gentle stimulant, without any injurious reaction. It produces a 
restful feeling after exhausting efforts of mind or body; it tranquil- 
izes, but does not disqualify for labor, and hence it is highly 
esteemed by persons of literary pursuits. 

36. Another property of coffee is, that it diminishes the waste of 
the tissues, and consequently permits the performance of excessive 
labor upon an economical and inadequate diet. This has been 
tested among the miners of Belgium. Their allowance of solid 
food was below that found necessary in prisons and elsewhere; but, 
with the addition of about four pints of coffee daily, they were 
enabled to undergo severe labor without reducing their muscular 
strength. The caravans which traverse the deserts are supported 
by coffee during long journeys and lengthened privation of food. 
Among armies it is indispensable in supplementing their imperfect 
rations, and in relieving the sense of fatigue after great exposure 
and long marches. When taken with meals, coffee is also thought 
to promote digestion. 

34. Lead in pipes and other things ? Advice ? What takes place after the articles of 
lead have been used much ? What is wise ? 

35. Coffee as an article of diet ? Of what does it consist ? How does the water affect the 
coffee? The peculiar stimulant ? How does it affect most persons ? 

36. Another property of coffee ? Miners of Belgium? The Caravans? Among armies ? 
Taken with meals? 



FOOD AND DRINK. 97 

|87. Tea. — The effects of tea-drinking are very similar to those of 
coffee, and are due to a peculiar principle called theine. This prin- 
ciple is probably the same as that found in coffee — caffeine — since the 
chemical composition of both is precisely alike. Tea, as a beverage, 
is made from the dried leaves of the plant by the addition of hot 
water; if the tea be boiled, the oil which gives it its agreeable 
flavor is driven off with the steam. There are two kinds of tea — ■ 
the black and the green ; the latter is sometimes injurious, produc- 
ing wakefulness and other nervous symptoms. The excessive use 
of either coffee or tea will cause wakefulness. 

38. During Dr. Kane's expedition in the Arctic regions, the 
effects of these articles were compared. " After repeated trials, the 
men took most kindly to coffee in the morning, and tea in the 
evening. The coffee seemed to continue its influence throughout 
the day, and they seemed to grow hungry less rapidly than after 
drinking tea, while tea soothed them after a day's hard labor, and 
the better enabled them to sleep. They both operated upon 
fatigued men like a charm, and their superiority over alcoholic 
stinndants was very decided." 

39. Chocolate is made from the seeds of the cocoa-tree, a native 
of tropical America. Its effects resemble somewhat those of tea and 
coffee, but it is very rich in nutriment. Linnaeus, the botanist, 
was so fond of this beverage, that he gave to the cocoa-tree the 
name Theobroma — " the Food of the Gods." Its active principle 
is theobromin. 

40. Alcohol. — The word alcohol is of doubtful origin. It is 
commonly supposed to be derived from the Arabic language, several 
words in that tongue resembling it in sound, but none of them or 
any other in the language have a meaning corresponding with that 
of the English term. 

41. History. — Alcohol was distilled from rice many centuries 
before that seed was known in Europe. We hear of it in Bagdad 
about the year 900. It was known to the Moors of Spain, through 



37. Effects of tea-drinking? Peculiar principle? The tea beverage, how made? Black 
and green tea ? Excessive use of tea or coffee ? 

38. Experiments made during Kane's expedition? 

39. State what is said of chocolate. 

40. In what language has the word alcohol its origin ? 

41. Give its history. 

5 



98 FOOD AND DRINK. 

whom the knowledge of its production spread into Western Europe. 
The first description of alcohol was given by a western writer about 
1280, who wrote of a "burning or ardent water " that resulted 
from the distillation of wine. It may also have been known to the 
Romans, for Pliny, in the first century, wrote of a strong kind of 
wine that was inflammable — a quality that strongly suggests the 
knowledge of a product of distillation. 

42. The Alcohols. — There are at least twelve members of the 
alcohol family, the oldest of which is common alcohol. This last 
is the only one that need be referred to here. Common Alcohol is 
sometimes known as spirit of wine, also as vinic alcohol. It is 
commonly obtained by the distillation of grains or of wine. The 
ardent spirits of commerce (brandy, whiskey, gin, and rum) contain 
about one-half water, the other half alcohol. Alcohol is also found 
in all the wines and malt liquors (beer, ale, and porter) in varying 
proportions. The juices of ripe, sweet fruits will, at seventy degrees, 
of Fahrenheit, begin spontaneously to "work" or ferment; also 
wheat and other starch-grains, when sprouting, will have their 
starch changed into sugar, and this, in like manner, will undergo 
fermentation — alcohol being one of the results of this action in 
both cases. 

43. Properties of Alcohol. — Alcohol is a clear, colorless, vola- 
tile, and inflammable liquid of penetrating odor and burning taste. 
It is lighter than water. As it cannot be frozen, it is used in 
thermometers for taking low or exceedingly cold temperatures. It 
is also used in spirit levels. It burns with a pale, bluish flame, 
without smoke, and with intense heat ; hence its use in the spirit- 
lamp. 

44. Is Alcohol Food ? — Some authorities class alcohol among 
the food substances. Chemically it is allied to the sugars, but the 
effect of alcohol within the body is very unlike that of the sugars. 
The latter are nourishing, while the former tends to impair nutri 
tion. It was on the mistaken theory that alcohol had sustaining 
power, that for two hundred years the armies and navies of certain 
countries were supplied with rations of rum or some other alcoholic 

42. How is common alcohol obtained ? 

43. What are the properties of alcohol? 

44. What co,n you say of alcohol as a food ? 



FOOD AND DRINK. 99 

drink, under the name of " grog." During recent years, a systematic 
inquiry has been made to discover whether the grog-ration was 
really serviceable or the reverse. Tests have been tried upon con- 
siderable bodies of men, under military discipline, by withdrawing 
that ration; comparisons have been made at home and abroad, in 
hot climates and in cold, in active service and at rest. The results 
of these observations have, without exception, been favorable to 
the non-use of spirits. The proportion of ill-health, the number of 
sick days, and the incapacity for work have invariably been greater 
among the men to whom the spirit-ration has been issued, the qual- 
ity of food and other circumstances being made as nearly equal as 
possible. Hence the conclusion that not only is alcohol not a food, 
but is injurious in itself, and a detriment to the food taken. 

45. Does Alcohol Relieve Thirst? — One of the most striking 
properties of alcohol is its affinity for water. When swallowed, there- 
fore, its tendency is to deprive the body of water, and to create 
thirst rather than to relieve it. It may then be stated that alcoholic 
drinks which appear to quench thirst do so by means of the water 
that, in greater or less quantities, dilutes the alcohol they contain. 
Water, the peerless beverage of nature, does its work better in pro- 
portion as it remains free from alcohol. To maintain normal ac- 
tion, the delicate organs of the body require a uniform supply of 
water. When alcohol is introduced, it draws the water to itself, 
and leaves the organs without their share of proper moisture; 
hence, after death from alcoholism, we find them affected in dif- 
ferent degrees, being drier and harder than is natural. 

46. Does Alcohol Enable its Consumers to Resist Extreme 
Cold ? — If this could be proved to be a fact, some of its boasted 
usefulness would receive support. In extremely cold climates, the 
inhabitants are enabled to live comfortably by consuming vast 
quantities of animal food alone, especially if it is abundantly oily. 
Will alcohol act in a similar way or assist in maintaining heat? 
Experience and observation say no. 

47. Before the thermometer was applied to the testing of the 
body's temperature, it was commonly supposed, by reason of the 

45. Does alcohol relieve thirst? 

46. Does alcohol enable one to resist cold ? 

47. How is the temperature of the body affected? 



100 FOOD AND DRINK. 

sensations of warmth, that alcohol increased bodily heat. When, 
however, this new test was applied, it became apparent that those 
sensations were deceptive, and that there had been an actual fall in 
temperature as the result of imbibing alcohol. The surface of the 
stomach is irritated by this powerful agent, causing the nerves of 
sensation to convey to the brain the impression that something has 
entered the stomach which is producing warmth. This is a delusive 
impression, as we know, by pouring a few drops of alcohol on the 
skin, that the tendency of alcohol is to cool the surface whenever 
evaporation can take place. 

48. The sensation of warmth of the face and surface of the body 
is also deceptive. The flushing of the face, common to hard 
drinkers, does not indicate that they have a superabundance of 
animal heat, the temperature of their bodies being below normal. 
The true cause of the flush is a paralysis of one set of nerves govern- 
ing the natural action of the hair-like vessels that course just below 
the skin. Nature has provided these infinitely fine vessels with 
minute controlling nerves, whose duty it is to regulate the flow of 
blood in exposed positions. Alcohol paralyzes this control ; the 
blood flows at random, and the terminal vessels are overcharged 
with blood. Hence, the high color, which is so remarkable in 
habitual drinkers that it amounts to a disfigurement is Nature's 
signal of distress, showing that the circulation is deranged, and the 
blood is unduly brought into contact with the lower temperature of 
the outer air. Alcohol, therefore, is not a producer of heat, but a 
promoter of cold, and must be dangerous to any persons taking it 
when they are exposed to low temperatures. {Read Note 13.) 

49. The testimony of those who have had experience in contact 
with the realms of snow and ice is unanimous against the cold- 

13. Dr. Rae's Statement. — " The Arctic explorer, Dr. Rae, states that he 
found entire avoidance of alcohol necessary in the far North. The moment a 
man had swallowed a drink of spirits, it was certain that his day's work was 
nearly at an end. ' It was absolutely necessary that the rule of total absti- 
nence should be rigidly enforced, if we would accomplish our day's task. Any 
use of liquor, as a beverage, when we had work on hand, in that terrific cold, 
was out of the question. ' " 

48. Of what is the flushed face of drinkers the index ? 

49. What do travelers in cold countries say of its use? 



FOOD AND DRINK. 101 

resisting property of alcohol. It is recorded of the men who 
served in Napoleon's campaign in Russia, under great exposure to 
cold, that death was hastened by the use of alcohol. The evidence 
of the Monks of St. Bernard is similar. Numerous Arctic explorers 
testify that not only is the temporary indulgence liable to result in 
most serious consequences, but that strong, able-bodied men in the 
habit of using alcoholic drinks are entirely unfitted to resist the 
cold to which they must be exposed. The natives and travelers 
alike rely upon fresh animal food, especially fatty food, and avoid 
alcohol as a danger to life.* 

50. Alcohol Destructive to Life. — Instead of being a promoter 
of life, as the early alchemists who produced it hoped it would be, 
alcohol is hostile to life ; it is a poison. Plant life is speedily de- 
stroyed when brought into close contact with it. The lower animals 
are poisoned by it. When applied directly to small insects and 
reptiles, death commonly occurs in a few seconds or minutes. It is 
hurtful to the larger animals, and the more intelligent of them 
appear to resent its use instinctively. This is seen when dogs have 
been forced to take brandy in small doses for some time. Instead 
of learning to like it, they gradually show a greater and greater dis- 
like to it. y 

51. The Proper Use of Alcohol. — Like opium, chloral, arsenic, 
and many other poisons, alcohol may be rightly used, and that 
is as a medicine. Tor the relief of sickness and feebleness of body, 

* "Alcohol is not the warming cordial and invigorating stimulant that it 
is reputed to be, but there is a world-full of preconceived opinions in its favor 
that must be met and overcome before the true view can make its way. But 
the truth must prevail at last. Its true place is not along with the displays 
of wealth and luxury upon our sideboards, but in the medicine-chest along 
with hasheesh, henbane, opium, stramonium, and so forth, labeled as a Poi- 
son !"— Dr. A. F. Kinne. 

+ " There is no such thing as a temperate use of spirits. In any quantity 
they are an enemy to the human constitution. Their influence upon the 
physical organs is unfavorable to health. They produce weakness, not 
strength ; sickness, not health ; death, not life." — Dr. Aldcn. 



50. What is the effect of alcohol upon life? 

51. What is the proper use of alcohol ? 



102 FOOD AND DRINK. 

or conditions of unusual fatigue, alcohol can he beneficially used 
under the advice of a physician. {Read Note 14.) 

14. Adulteration in Liquors. — " It is not enough that alcoholic drinks 
are dangerous when purely made, but there is an added danger growing out of 
the almost universal practice of the manufacturers of these drinks to tamper 
with them and adulterate them with other harmful materials. Not many 
months ago the city government of Paris caused a testing of all the wines 
that were brought into the market during a month ; there were 1,518 samples 
of French wine examined, and only 65 found absolutely free from injurious 
addition — that is, less than 5 per cent, was really pure.'' — N. Y. Scientific 
Times. 



QUESTIONS FOR TOPICAL REVIEW. 

PAGE 

1. How is the necessity for food shown ? 81 

2. To what process of waste and repair is the body constantly subjected ? 81 

3. How do you account for the sensations of hunger and thirst ? 82 

4. What further can you state having relation to the subject ? 82 

5. What can you state in regard to the quantity of food required for the support of life ? 83 

6. What circumstances change the needs of persons, old and young, as regards food 

and drink ? 83 

7. What becomes of all the food and drink we consume ? 85 

a What further can you state in relation to the process of renovation through which 

the body passes ? 85 

9. What can you state of the habit of nations in respect to diet ? 85 

10. What in relation to the selection of articles *cr food ? 86 

11. What has been proved as regards animal food ? 86 

12. What as respects the necessity for changing or varying the diet ? 87 

13. Of what importance is milk as an article of food? 87 

14. What are the constituents of milk ? 87 

15. What can you state of eggs as an article of food? 88 

16. Of the meats, so called, as an article of food? 88 

17. What effect does cold have upon meats ? 89 

18. In what other way may beef and pork be preserved ? , 89 

19. What can you state of salted meat as food, and of its continued use ? 89 

20. What change does meat undergo in the cooking ? 89, 90 

21. What directions are given for boiling meat? 89 

22. What for roasting, and with what results ? 90 

23. What is said about the frying of meats? 90, 91 

24. Give the statement in relation to trichina 91 

25. State what is said in relation to fish 91 

26. What is stated of the usefulness and other properties of the products of the vege- 

table kingdom ? 91 

27. What further is said of vegetable food ? 91 

28. Why is bread made of wheat-flour so important as an article of food ? 92 

29. State whatever else you can in relation to bread 92, 93 

30. Give the statement respecting the potato 93 

31. What is stated of fruits, the use of them, their nutritious qualities, etc 93 

32. How general is the existence of perfectly pure water?. . 94 

83. What is stated in relation to drinking water ? 94 

34. What effect has the action of water upon lead? 95 

35. What further can you state on the subject ? 96 

36. What properties has coffee as an article of diet? 96 

37. In what circumstances has coffee been found peculiarly beneficial ? 96 

38. What comparison is made between coffee, tea, and chocolate ? 97 

39. How are the wines, and malt, and other alcoholic beverages produced ? 97, 98 

40. What articles are employed in their production ? 9S 

41. What are the properties of alcohol ? 98 

42. Is alcohol a food? 98 

43. What is said of the property of alcohol to relieve thirst? 99 

44. What effect does alcohol have upon the body's temperature ? 99 

45. What is the cause for flushing of face in drinkers? 100 

46 . What is the testimony of Arctic explorers and others ? 100, 101 

47. What the effect of alcohol upon plant and animal life ? 101 

48. What are the only conditions for use of alcohol? 101 



CHAPTER VL 

Digestion. 

The Principal Processes of Nutrition — The General Plan of Digestion — Mastica- 
tion — The Teeth — Preservation of the Teeth — Action of tJie Saliva — The 
Stomach and the Gastric Juice — The Movements of the Stomach — Gastric 
Digestion — The Intestines — The Bile and Pancreatic Juice — Intestinal Di- 
gestion — Absorption by means of Blood-vessels and Lacteals — The Lymphatic 
or Absorbent System — TJie Lymph — Conditions which affect Digestion — The 
Quality, Quantity, and Temperature of the Food — The Influence of Exer- 
cise and Sleep — The Kidneys — The Spleen — Effect of Alclwhol on Digestion, 
the Liver, and Kidmeys. 

1. Nutrition. — The great design of food is to give nutriment or 
nourishment to the body. But this is not accomplished directly, as 
the food must first pass through certain preparatory changes, as 
follows : (1), Digestion, by which the food is reduced to a soluble 
condition; (2), Absorption, by which, when digested, it is taken 
into the blood ; (3), Circulation, which carries the enriched blood 
to the various parts of the system ; and (4), Assimilation, by which 
each tissue selects from the blood the materials necessary for its 
support. 

2. By these four steps the sustaining power of food is gradually 
brought into exercise and the vital machinery kept in working 
order, somewhat after the manner of the steam-engine. To operate 
the latter, the force imprisoned within the coal and water is set free 
and converted into motion by the burning of the fuel and the vapor* 
ization of the water. It will be seen, however, when we come to 
study these operations in the human body, that they are conducted 
silently and harmoniously, with marvellous delicacy and complete- 
ness, and without that friction, and consequent loss of power, which 
attend the working of the most perfect machinery of man's inven- 
tion. — 

1. Design of food ? How accomplished ? 

2. Sustaining power of food ? Simile of the engine? Operation in the human body? 



DIGESTION. 



105 



3. General Plan of Digestion. — The great change which food 
undergoes in digestion is essentially a refining process, reducing 
articles of diet, which are at first more or less solid, crude, and 
coarse, to a liquid and finely comminuted condition, suitable for 
absorption into the blood. The entire 

process of digestion takes place in what 
is called the " alimentary canal," a nar- 
row, crooked tube, about thirty feet in 
its entire length. Tins canal begins in 
the mouth, extends thence downward 
through the gullet to the stomach (a re- 
ceptacle in which the principal work of 
digestion is performed), and thence on- 
ward through the small and large intes- 
tines. 

4. The stomach and intestines are 
situated in the cavity of the abdomen 
(Fig. 20, C, and Fig. 26), and occupy 
about two-thirds of its space. The ac- 
tion to which the food is subjected in 
these organs is of two kinds — mechani- 
cal and chemical. By the former it is 
softened, agitated, and carried onward 
from one point to another ; by the lat- 
ter it is changed in form through the 
solvent power of the various digestive 
fluids. 

5. Mastication. — As soon as solid 

food is taken into the mouth, it undergoes mastication or chewing. 
It is caught between the opposite surfaces of the teeth, and by them 
is cut and crushed into very small fragments. In the movements 
of chewing, the lower jaw plays the chief part ; the upper jaw, hav- 
ing almost no motion, acts simply as a point of resistance, to meet 
the action of the former. These movements of the lower jaw are 




Fig. 20.— Section of the Trunk, 
showing the cavities of the 
Chest and Abdomen. 



8. Change of food in digestion ? Process of digestion ? Describe the alimentary canal. 

4. Situation of the stomach and intestines? Action of the food? Mechanical action? 
Chemical ? 

5. Describe the process of mastication. How many and what movements ? 



106 



DIGESTION. 



of three sorts : an up-and-down or cutting, a lateral or grinding, and 
a to-and-fro or gnawing motion. 

6. The teeth are composed of a bone-like material, and are held 
in place by roots running deeply into the jaw. The exposed por- 
tion, or " crown," is protected by 
a thin layer of enamel (Fig. 21, a), 
the hardest substance in the body, 
and, like flint, is capable of strik- 
ing fire with steel. In the interior 
of each tooth is a cavity, contain- 
ing blood-vessels and a nerve, 
which enter it through a minute 
opening at the point of the root 
(Fig. 23). 

7. There are two sets of teeth ; 
first, those belonging to the earlier 
years of childhood, called the milk 
teeth, which are twenty in number 
and small. At six or eight years 
of age, when the jaw expands, and 
when the growing body requires a 
more powerful and numerous set, 
the roots of the milk teeth are ab- 
sorbed, and the latter are " shed," 
or fall out, one after another (Fig. 
22), to make room for the permanent set. 

8. There are thirty-two teeth in the permanent set, an equal 
number in each jaw. Each half-jaw has eight teeth, similarly 
shaped and arranged in the same order ; thus, two incisors, one 
canine, two bicuspids, and three molars. The front teeth are small, 
sharp, and chisel-edged, and are well adapted for cutting purposes ; 
hence their name incisors. The canines stand next, one on each 
side of the jaw ; these receive their name from their resemblance 
to the long, pointed tusks of the dog (Fig. 23). 




Fig. 21. — Section of a Tooth. 

a, Enamel ; 6, Cavity ; c c, Roots ; 

d, Body of the Tooth. 



6. Composition of the teeth ? Enamel of the teeth ? Interior of teeth ? 

7. The milk teeth? The permanent teeth? 

8. 9. Number of teeth ? How arranged ? 



DIGESTION. 



107 



9. The bicuspids, next in order, are larger and have a broader 
crown than the former; while behind them are the molars, the 
largest and most powerful of the entire set. These large back 




Fig. 22.— Section op the Jaws. 
1' 2' 3' 4? 5', The Milk Teeth ; 1" to 8", The Germs of the Permanent Set 

teeth, or " grinders," present a broad, rough surface, suitable for 
holding and crushing the food. The third molar, or "wisdom tooth," 
is the last to be cut, and does not appear until about the twenty- 
first year. The arrangement of the teeth is indicated by the fol- 
lowing dental formula : 

M -3- 




10. It is interesting, at this point, to notice the different forms 

10. Different forms of teeth? Human teeth? The inference? 



108 



DIGESTION. 



of teeth in different animals, and observe how admirably then 
teeth are suited to the respective kinds of food upon which they 
feed. In the carnivora, or flesh-feeders, the teeth are sharp and 
pointed, enabling them both to seize their prey and tear it in pieces ; 




Fio. 23.— Section of the Jaws— Right Side. 
V, A, N, Vsins, Arteries, and Nerves of the Teeth. The root of one tooth in each jaw is cut 
vertically to show the cavity and the blood-vessels, etc., within it. 1 to 8, Permanent 
Teeth. 

while the herbivora, or vegetable-feeders, have broad, blunt teeth, 
with rough crowns, suitable for grinding the tough grasses and 
grains upon which they feed. Human teeth partake of both forms ; 
some of them are sharp, and others are blunt ; they are therefore 
well adapted for the mastication of both flesh and vegetables. 



Xb 



DIGESTION. 109 

Hence we infer that, although man may live exclusively upon either 
vegetable or animal food, he should, when possible, choose a diet 
made up of both varieties. 

11. Preservation of the Teeth. — In order that the teeth shall 
main in a sound and serviceable condition, some care is of course 

requisite. In the first place, they require frequent cleansing ; for 
every time we take food, some particles of it remain in the mouth; 
and these, on account of the heat and moisture present, soon begin 
to putrefy. This not only renders the breath very offensive, but 
piomotes decay of the teeth. 

12. The saliva, or moisture of the mouth, undergoes a putrefac- 
tive change, and becomes the fertile soil in which a certain minute 
fungus has its growth. This fluid, too, if allowed to dry in the 
mouth, collects upon the teeth in the form of an unsightly, yellow 
concretion, called tartar. To prevent this formation, and to remove 
other offensive substances, the teeth should be frequently cleaned 
with water, applied by means of a soft tooth-brush. The preven- 
tion of the tartar fungus is best effected by the use of a weak solu- 
tion of carbolic acid. {Read Note i. ) 

1. The Proper Care of the Teeth. — "In the famous history of Don 
Quixote, the hero of La Mancha, it is related that at the end of one of' his 
great battles, wherein he was as usual conquered, he found himself wounded 
in the face by a violent blow from a stone, and grieved to find that with it he 
had lost one of his teeth. Reflecting awhile on this unhappy accident, he 
sagely remarked that to lose a molar was very much like losing an old friend. 
And it is an important question, in view of this bit of wisdom, how to care for 
the molars, that they may become old friends. To this end, the cardinal 
maxim is cleanliness ; and again cleanliness. One means of cleansing is the 
natural one— that is, by chewing food ; for it is well known that if we have a 
tooth so situated in the jaw that it is seldom brought into use, that tooth early 
shows signs of decay. But more effectual is the artificial means— the brush. 
Children should early be taught to use this ; and for them a softer brush 
should be selected than for adults. They should also early be taught to use 
no metallic substances, as pins, needles, etc., to remove substances from be- 
tween the teeth. The teeth should always be thoroughly cleansed after taking 
acids into the mouth— for they are the great enemies to the teeth— and also 
after candies and other forms of sugar, for their particles that linger on the 



11. Cleaning of teeth? Effects of not cleaning? 

12. Effects of the saliva ? Formation of tartar ? How prevented ? How destroyed ? 



110 



DIGESTION. 



13. It should be borne in mind that the enamel, JNature's protec- 
tion for the teeth, when once destroyed, is never formed anew ; and 
the body of the tooth thus exposed is liable to rapid decay. On this 
account, certain articles are to be guarded against ; such as sharply 
acid substances that corrode the enamel, and hard substances that 
break or scratch it — as gritty tooth-powders, metal tooth-picks, and 
the shells of hard nuts. Sudden alternations from heat to cold, 
when eating or drinking, also tend to crack the enamel. 

14. Action of the Saliva. — While the morsel of food is cut and 
ground by the teeth, it is at the same time intimately mixed with 

the saliva, or fluids of the 
mouth. This constitutes 
the second step of diges- 
tion, and is called insali- 
vation. The saliva, the 
first of the digestive solv- 
ents, is a colorless, wa- 
tery, and frothy fluid. It 
is secreted (/. e., separated 
from the blood) partly by 
the mucous membrane 
which lines the mouth, 
but chiefly by the salivary 
glands, of which there are three pairs situated near the mouth. 

15. These glands consist of clusters of very small pouches, around 
which a delicate network of blood-vessels is arranged ; they empty 
into the mouth by means of little tubes, or ducts. The flow from 
these glands is generally sufficient to maintain a soft and moist 
condition of the tongue and mouth 




Fig. 24.— Structure of a Salivary Glant>. 



but when they are excited bv 



teeth are changed by decomposition into lactic acid. Occasional examination 
of the teeth is prudent, in order that a commencing cavity may be promptly 
detected and remedied. Teeth that are decayed beyond remedy by filling 
should be immediately removed."— Lane on tlte Hygiene of the Teeth. 



13. Destruction of the enamel ? How guarded against ? 

14. Mixing of food with the saliva ? What is the saliva? How secreted? The salivary 
glands? 

15. The flow of saliva ? The thought of food ? Anxiety and grief? Animals fed upo* 
dry and .coarse food ? 




DIGESTION. Ill 

the presence and taste of food, they pour forth the saliva more 
freely. Even the mere thought of food will at times cause the 
saliva to flow, as when the ap- 
petite is stimulated hy the sight 
or smell of some savory article ; 
so that the common expression 
is correct that "the mouth wa- 
ters " for the favorite articles of 
food. Anxiety and grief pre- 
vent its flow, and cause " the 
tongue to cleave to the roof of 
the mouth." In the horse, and 
other animals that feed upon 
dry and coarse fodder, and re- FlG . 25 .- the head of a Horse, showing the 

rmirP an nhrmrlflTif <;nrmlv ni large salivary gland (a), its duct (6), the mus- 

quire an aounaant supply 01 cles of masticat i n (c, a, e, /, and g). 

saliva, we find large salivary 

glands, as well as powerful muscles of mastication. 

16. The mingling of the saliva with the food seems a simple 
process, but it is one that plays an important part in digestion. In 
the first place, it facilitates the motions of mastication, by moistem 
ing the food and lubricating the various organs of the mouth. 
Secondly, it prepares the way for other digestive acts : by the action 
of the teeth, the saliva is forced into the solid food, softens the 
harder substances, and assists in converting the whole morsel into 
a semi-solid, pulpy mass, that can be easily swallowed, and readily 
acted upon by other digestive fluids. The saliva, also, by dissolv- 
ing certain substances, as sugar and salt, develops the peculiar taste 
of each ; whereas, if the tongue be dried and coated, they are taste- 
Jess. Hence, if substances are insoluble, they are devoid of taste. 

17. Finally, the saliva has the property of acting chemically upon 
the food. As we have before stated (Chap. IV.), starch, as starch, 
cannot enter the tissues of the body ; but, in order to become nutri- 
ment, must first be changed to grape-sugar. This change is, in 
part, effected by the saliva, and takes place almost instantly, when- 
ever it comes in contact with cooked starch. This important func- 

16. Importance of the process ? The first place? The second? The third? 

17. Its final importance ? Starch ? How effected ? Ptyalin 1 



112 DIGESTION. 

tion is due to an organic ingredient of the saliva called ptyalin. 
This substance has been extracted from the saliva by the chemist, 
and has been found, by experiment, to convert into sugar two thou- 
sand times its own weight of starch. {Read Note 2.) 

18. Importance of Mastication and Insalivation. — Each of 
these processes complements the other, and makes the entire work 
available ; for, by their joint action, they prepare the food in the 
best possible manner for further digestive changes. The study of 
these preliminary functions will appear the more important, when 
we reflect that they are the only ones which we can regulate by the 
will. For, as soon as the act of swallowing begins, the food not 
only passes out of sight, but beyond control ; and the subsequent 
acts of digestion are consequently involuntary and unconsciously 
performed. 

19. It is generally known that rapid eating interferes with diges- 



2. The First Step of Digestion. — "The digestive process begins in 
the mouth ; among civilized people it begins in the plate, or even before. 
Undoubtedly mastication is the natural method of mincing meat, and not the 
least of its value lies in the fact that it takes time. A man who is eating a 
tough, and therefore not very digestible chop, will be slow in eating, if he is 
careful to masticate it well. There will be a long interval between each 
mouthful, and the stomach will run no risk of being hastily loaded. 

"Now, a hastily-loaded stomach is as bad almost as, or rather, is the same 
thing as, an overloaded stomach ; and there can be no doubt that artificial 
mastication becomes a snare when it leads any one to introduce a large quan- 
tity of finely-minced meat suddenly and rapidly into an unprepared stomach, 
especially into the feeble stomach of an invalid, under the idea that, because 
the meat is so nicely minced, and so very tender, it can be no possible burden 
to that sorely-tried organ. Natural mastication has, besides, another advan- 
tage over the artificial process, which is perhaps not always recognized. 
Whenever food enters the mouth, it gives rise to what is called a flow of saliva. 
This saliva is secreted by certain glands, which pour into the mouth the fluid 
they strain off from the blood, and which are excited or stimulated to action 
by the presence of food in the mouth, as well as by other causes. Saliva rap- 
vlly changes starch into sugar, and sugar is pre-eminently a soluble body, pass- 
ing with the greatest ease from the alimentary canal into the blood." — People's 
Magazine {London). 

18. Each of the processes ? Why is a knowledge of the digestive functions important ? 
How shown ? 

19. Rapid eating? Describe the process and effects. 



DIGESTION. 1 13 

tion. How does this occur ? In the first place, in rapid eating, the 
flow of the saliva is insufficient to moisten the solid parts of the 
food, so that they remain too hard and dry to be easily swallowed. 
This leads to the free and frequent use of water, or some other 
beverage, at meals, to " wash down " the food — a most pernicious 
practice. For these fluids not only cannot take the place of the 
natural digestive juices, but, on the contrary, dilute and weaken 
them. 

" 20. Secondly, the saliva being largely the medium of the sense 
of taste, the natural flavors of the food are not developed, and con- 
sequently it appears comparatively insipid. Hence the desire for 
highly-seasoned food, and pungent sauces, that both deprave the taste 
and over excite the digestive organs. Rapid eating also permits 
the entrance of injurious substances which may escape detection by 
the taste, and be unconsciously received into the system. In some 
instances, the most acrid and poisonous substances have frequently 
been swallowed " by mistake," before the sense of taste could act, 
and demand their rejection. 

21. Thirdly, the food, being imperfectly broken up by the teeth, 
is hurried onward to the stomach, to be by it more thoroughly 
divided. But the stomach is not at all adapted to perform the task 
thus imposed upon it; and the crude masses of food remain a heavy 
burden within the stomach, and a source of distress to that organ, 
retarding the performance of its proper duty. Hence persons who 
habitually eat too rapidly, frequently fall victims to dyspepsia.* 
Rapid eating also conduces to overeating. The food is introduced 
so rapidly, that the system has not time to recognize that its real 
wants are met, and hence the appetite continues, although more 
nutriment has been swallowed than the system requires, or can 
healthfully appropriate. 

22. The Stomach. — As soon as each separate portion of food is 
masticated and insalivated, it is swallowed ; that is, it is caused to 
move downward to the stomach, through a narrow muscular tube 

* For the same reason, persons who prematurely lose their teeth suffer from 
dyspepsia. For them a proper means of relief is the use of artificial teeth. 

20. Loss of taste? Another effect of rapid eating? Mistakes 'j 

21. Effect of imperfectly-broken food in the stomach ? Dyspepsia? Over-eating? 

22. Gullet? Describe the stomach and its location. Effects of gormandizing? 



114 



DIGESTION. 



about nine inches in length, called the oesophagus, or gullet (Fig. 27). 
The stomach is the only large expansion of the digestive canal, and 
is a most important organ of digestion. It is a hollow, pear-shaped 

pouch, having a capacity of 
three pints, in the adult. 
Its walls are thin and yield- 
ing, and may become unnat- 
urally distended, as in the 
case of those who subsist 
on a bulky, innutritious diet, 
and of those who habitually 
gormandize. 

23. The stomach has also 
two openings; that by which 
food enters, being situated 
near the heart, is called the 
cardiac, or heart orifice; the 
other is the pylorus, or 
" gatekeeper," which guards 
the entrance to the intes- 
tines, and, under ordinary 
circumstances, permits only 
such matters to pass it as 
have first been properly 
acted upon in the stomach. 
Coins, buttons, and the like 
are, however, readily allowed 
to pass, because they can be of no use if retained. The soft and 
yielding texture of this organ — the stomach — indicates that it is not 
designed to crush and break up solid articles of food. 

24. The Gastric Juice. — We have seen how the presence of 
food in the mouth excites the salivary glands, causing the saliva 
quickly to flow. In the same manner, when food reaches the 
stomach, its inner lining, the mucous membrane, is at once excited 
to activity. At first, its surface, which while the stomach is empty 

23. Heart-orifice? Gatekeeper? Coins, etc.? Indication of the soft and yielding texture 
of the stomach ? 

34. What is meant by the gastric juice? 




Fio. 26. — Section of Chest and Abdomen. 



A, Heart. 

B, The Lungs. 

C, Diaphragm. 

D, The Liver. 



E, Gall Bladder. 

F, Stomach. 

G, Small Intestine. 
H, Large Intestine. 



DIGESTION. 



115 



presents a pale pink hue, turns to a bright red color, for the minute 
blood-vessels which course through it are filled with blood. Pres- 
ently a clear, colorless, and acid fluid exudes, drop by drop, from 
millions of little tubes in the inner 
surface of the stomach, until finally 
the surface is moistened in every part, 
and the fluid begins to mingle with the 
food. This fluid is termed the gastric 
juice. 

25. The gastric juice dissolves cer- 
tain articles of food, especially those 
belonging to the albuminoid class. This 
solvent power is due to its peculiar in- 
gredient, pepsin ; in digestion, this sub- 
stance acts like a ferment — that is, it 
induces changes in the food simply by 
its presence, but does not itself undergo 
change. The acidity of the gastric 
juice, which is due to lactic acid, is not 
accidental ; for we find that the pepsin 
cannot act in an alkaline solution — 
that is, one which is not acid or neutral. 
The quantity of gastric juice secreted 
daily is very large, probably not less 
than three or four pints at each meal. 
Though this fluid is at once used in 
the digestion of the food, it is not 
lost ; since it is soon re-absorbed by 
the stomach, together with those parts 
of the food which it has digested and 
holds in solution. 

26. Movements of the Stomach.— „. 

Pig. 27. Alimentary Canal— incrao 
The inner COating of the Stomach is ing Gullet, Stomach, Large and 
, Small Intestines. 

the mucous membrane, which, as we 

have seen, furnishes the gastric juice. Next to this coating lies 

25. What is the office of the gastric juice? Acidity of the gastric juice? Quantity of 
gastric juice used ? What becomes of it ? 

26. Muscular coat of the stomach ? Expansion and contraction of its fibres 1 Action of 
the fibres? 




116 DIGESTION. 

another, called the muscular coat, composed of involuntary muscular 
fibres, some of which run circularly, and others in a longitudinal 
direction. These expand to accomodate the food as it is introduced, 
and contract as it passes out. In addition, these fibres are in con- 
tinual motion while food remains in the stomach, and they act in 
such manner that the contents are gently turned round from side 
to side, or from one end of it to the other. 

27. By these incessant movements of the stomach, called the 
peristaltic movements, the gastric juice comes in contact with all 
parts of the food. We are, however, not conscious that these 
movements take place, nor have we the power to control them. 
When such portions of the food as are sufficiently digested approach 
the pylorus, it expands to allow them to pass out, and it closes 
again to confine the residue for further preparation. 

28. The knowledge of these and other interesting and instruc- 
tive facts has been obtained by actual observation; the workings of 
the stomach of a living human being have been laid open to view 
and examined — the result of a remarkable accident. Alexis St. 
Martin, a Canadian voyageur, received a gun-shot wound which laid 
open his stomach, and which, in healing, left a permanent orifice 
nearly an inch in diameter. Through this opening the observer 
could watch the progress of digestion, and experiment with different 
articles of food. Since that occurrence, artificial openings into the 
stomach of the inferior animals have been repeatedly made, so that 
the facts of stomach-digestion are very well ascertained and verified. 
{Read Note 3.) 

29. Gastric Digestion. — What portions of the food are digested 
in the stomach 1 It was formerly thought that all the great changes 
of digestion were wrought here, but later investigation has taught 
us better. We now know that the first change in digestion takes 

3. The Digestibility of Solid Foods.— "The accompanying table 
shows some of the results obtained from the experiments of Dr. Beaumont 
upon the stomach of Alexis St. Martin. It will surprise many to find that 



27. Peristaltic movements ? What is said of our consciousness of and power over these 
movements ? Describe the movement of the pylorus. 

28. How has the knowledge and the workings of the stomach been ascertained? St. 
Martin? How else? 

29. What was formerly thought? What do we now know? What else do we now know? 
Water, salt, and sugar? Absorption ? 



DIGESTION. 



117 



place in the mouth, by the partial conversion of starch into sugar. 
We also know that, of the three organic food principles (considered 
in Chapter IV.)' two — the fats and the sugars — are but slightly 
affected by the stomach; but that its action is confined to that third 
and very important class from which the flesh is formed, the albu- 
minoids. A few articles need no preparation before entering the 
system, as water, salt, and fruit-sugar. These are rapidly taken up 
by the blood-vessels of the stomach, which everywhere underlie its 
mucous membrane in an intricate and most delicate network. In 
this way the function of absorption begins. 

30. The albuminoid substances are speedily attacked and digested 
by the gastric juice. From whatever source they are derived, vege- 
table or animal, they are all transformed into the same digestive 
product, called albuminose. This is very soluble in water, and is 
in part absorbed by the blood-vessels of the stomach. After a 
longer or shorter time, varying from one to five hours, according to 
the individual and the quantity and quality of his food, the stomach 
will be found empty. ISTot only the unabsorbed digested food, but 
also those substances which the stomach could not digest, have 



vegetable foods — the) 
rule, as much time fo 

Food. 
"^Pork 


r are placed in the 
r digestion as ani] 

Time re- 

Mode of quired for 

Cooking. digestion. 

h. ni. 

.roasted 5 15 

.boiled 4 15 

.roasted 4 

. do 4 

.boiled 4 

.fried 4 

. do 3 30 

.hard boiled.. 3 30 
3 30 


latter part of the table — reqi 
nal food. 

t?„^ Mode of 
Food - Cooking. 

Salmon Trout boiled.. 

Eggs (whipped) raw 


Lire, as a 

Time re- 
quired for 
digestion. 
h. m. 
1 30 


Cartilage 

Ducks 


1 30 


Tripe (soused) boiled 

Pig's Feet (soused) do. . 

Cabbage boiled.. 

Beetroot do. . . 


1 


Fowls 

Do 


....1 
...4 


Beef 


....3 45 


*" Eggs 


Turnips . . do. . . 


3 30 


Do 


>Potatoes do. . 


3 30 






3 30 




.stewed 3 30 

. roasted 3 15 

.boiled 3 

.roasted 3 

.boiled 2 45 

.fricasseed 2 45 

.broiled 2 30 

.roasted : 2 30 

. do 2 30 

.boiled 2 30 

. do 2 25 

.roasted 2 15 

.boiled 2 

.broiled 2 . 

. do 1 30 


Carrot boiled . . 

Indian Corn Bread. . . baked . . 

Do. Cake do. 

Apple-dumpling boiled . 

Potatoes baked . . 


3 15 




.3 15 


Do 


.3 


""-Beef. 

Do 

Chicken 


....3 

2 33 

2 30 




Parsnips boiled . . 

Sponge Cake baked . . 

Beans boiled . . 

Apples (sour) . ." raw 

Barley boiled . . 


2 30 


Pig (suckling) 


....2 30 
2 30 


Gelatin 

Turkey 

Eggs 


....2 
....2 
... 2 


Cod Fish (cured, dry). ... 
Ox Liver . . . 


Sago do. 


....1 45 
1 30 






1 











30. Albuminose ? The process ? Chyme ? 



V 

\ st 



118 DIGESTION. 

passed little by little through the pylorus, to Undergo further action 
in the intestines. At the time of its exit the digested food is of a 
pulpy consistence, and dark color, and is then known as the chyme. 
{Read Note 4. ) 

31. The Intestines. — The intestines are continuous with the 
stomach, and consist of a fleshy tube, or canal, twenty -five feet in 
length. The small intestine, whose diameter is about one inch 
and a half, is twenty feet long, and very winding. The large in- 
testine is much wider than the former, and five feet long (Fig. 27). 
The general structure of these organs resembles that of the stomach. 
Like it, they are provided with a mucous membrane, or inner lin- 
ing, whence flow their digestive juices ; and, just outside of this, 
a muscular coat, which propels the food onward from one point to 
another. 

32. Moreover, both the intestines and stomach are enveloped in 
the folds of the same outer tunic or membrane, called the peri- 
toneum. This is so smooth and so well lubricated, that the intes- 
tines have the utmost freedom of motion within the abdomen. In 
the small intestines the work of digestion is completed, the large 
intestine receiving from them the indigestible residue of the food, 
and in time expelling it from the body. 

33. Intestinal Digestion. — As soon as the food passes the 
pylorus and begins to accumulate in the upper part of the intes- 
tines, it excites the flow of a new digestive fluid, which enters 
through a small tube, or duct, about three inches below the stom- 
ach. It is formed by the union of two distinct fluids — the bile and 
the pancreatic juice. The bile is secreted by the cells of the liver, 

4. Indigestible Matters. — "Children sometimes swallow coins, but- 
tons, etc., and so cause great alarm. There is little real ground for apprehen- 
sion under these circumstances, unless the coins are bronze. If the latter, 
there is some cause for fear that copper poisoning will ensue, and the ready- 
passage of the coin is desirable. This is best effected by meals of figs or pud- 
ding, in which the coins are imbedded, and so passed harmlessly. As to bulk, 
whatever will go into the stomach will pass the various straits and emerge 
again. " — Fothergill. 

31. What are the intestines? The small intestines? The large intestines? Their 
structure ? 

32. Peritoneum? The work of digestion? 

33. The presence of food in the intestines ? Bile ? , 



DIGESTION. 119 

the largest gland of the body, situated on the right side and upper 
part of the abdomen (Fig. 26). The bile is constantly formed, but 
it flows most rapidly during digestion. During the intervals of 
digestion it is stored in the gall-bladder, a small membranous bag 
attached to the under side of the liver. This fluid is of a greenish- 
yellow color, having a peculiar smell, and a very bitter taste. 

34. The pancreatic juice is the product of a gland called the 
pancreas, situated behind the stomach. This fluid is colorless, 
viscid, alkaline, and without odor. Like the digestive juices pre- 
viously described, it owes its solvent power to its peculiar ferments. 
The most important of these ferments, called pancreatin, transforms 
starch into sugar. Another, trypsin, causes the solution of undis- 
solved albuminoid substances ; and a third ferment, which has not 
received a name, causes a partial acidification of the fats. By the 
joint action of these fluids, the food is prepared for absorption. 
There results from this action of the pancreatic juice a white and 
milky fluid, termed the chyle, which holds in solution the digestible 
portions of the food, and is spread over the extensive absorbent 
surface of the small intestines. 

35. The mucous membrane of the intestines, also, secretes or 
produces a digestive fluid by means of numerous " follicles," or 
minute glands; this is called the intestinal juice. From experi- 
ments on the lower animals, it has been ascertained that this fluid 
exerts a solvent influence over each of the three organic food prin- 
ciples, and in this way completes the action of the fluids previously 
mentioned, viz.: — of the saliva in converting starch into sugar, of 
the gastric juice in digesting the albuminoids, and of the pancreatic 
juice and bile in emulsifying the fats. 

36. Absorption. — With the preparation of the chyle, the work of 
digestion is completed; but it has not yet become a part of the 
blood, by means of which it is to reach the different parts of the 
body. The process by which the liquefied food passes out of the 
alimentary canal into the blood is called absorption. This is 
accomplished in two ways; first, by the blood-vessels. We have 



34. The pancreatic juice ? The joint action of these fluids ? 

35. The mucous membrane? Experiments on inferior animals? 

36. How much thus far has been done with the food ? 



DIGESTION. 



seen how the inner membrane of the stomach is underlaid by a 
tracery of minute and numerous vessels, and how some portions of 
the food are by them absorbed. The supply of blood-vessels to the 
intestines is even greater; particularly to the small intestines, where 
the work of absorption is most actively carried on. 

37. The absorbing surface of the small intestines, if considered 
as a plane surface, amounts to not less than half a square yard. 
Besides, the mucous membrane is formed in folds with an immense 
number of thread-like prolongations, called villi, which indefinitely 
multiply its absorbing capacity. These villi give the surface the 
appearance and smoothness of velvet, and during digestion they dip 

into the canal, and, by means 
of their blood-vessels, absorb 
its fluid contents, just as the 
spongioles which terminate 
the rootlets of plants, imbibe 
moisture from the surround- 
ing soil. 

38. Secondly, absorption 
is also effected by the lac- 
teals, a set of vessels pecu- 
.Bliar to the small intestines. 
» These have their beginnings 
in the little villi just men- 
tioned, side by side with the 
blood-vessels. These two sets 
of absorbents run in different 
courses, but their destination 
is the same, which is the 
right side of the heart. The 
lacteals receive their name 
from their milky-white ap- 
pearance. After a meal containing a portion of fat, they are dis- 
tended with chyle, which they are specially adapted to receive ; at 
other times they are hardly discernible. The lacteals all unite to 




D B 

Fig. 28.— The Lacteals. 
A, Small Intestine. B, Lacteals. 
C, Thoracic Duct. D, Absorbents. 

E, Blood-vessel. 



37. The next process ? Give the first way ? 

38. How is absorption effected in another way? 
Thoracic duct ? 



Describe it. Name of the lacteals? 



DIGESTION. 121 

form one tube, the thoracic duct, which passes upward through the 
thorax, or chest, and empties into a large vein, situated just beneath 
the left collar-bone. 

39. The Absorbents. — The lacteals belong to a class of vessels 
known as absorbents, or lymphatics, which exist in nearly all parts 
of the body, except the brain and spinal cord. The fluid which 
circulates through the lymphatics of the limbs, and all the organs 
not concerned in digestion, is called lymph. This fluid is clear and 
colorless, like water, and thus differs from the milky chyle which 
the lacteals carry after digestion : it consists chiefly of the watery 
part of the blood, which was not required by the tissues, and is 
returned to the blood by the absorbents or lymphatics. {Read Notes.) 

40. Circumstances Affecting Digestion. — What length of 
time is required for the digestion of food 1 ? From observations 
made, in the case of St. Martin, the Canadian already referred to, 
it has been ascertained that, at the end of two hours after a meal, 

5. Absorption of the Lacteals. — "The force by which the milky fluid 
moves upward through the lacteals is very considerable. This has been 
proved by the distension of the whole system of vessels, including the thoracic 
duct, even to the occurrence of rupture, when that duct has been tied in an 
animal a short time before it has been fed. The movement of the fluid thus, 
in some measure, resembles absorption by the spongioles at the extremities of 
the roots of trees, and the continuous rising of the sap. The thoracic duct 
may become diseased, and a serious derangement of nutrition take place. 
In the case of an unfortunate person, who was some years ago exhibited as a 
curiosity under the name of the 'living skeleton,' was illustrated the slow 
starvation that may thus be produced. Although he was able to take food in 
abundant supply, he was not nourished by it. Finally he died, and an exami- 
nation of his body disclosed the fact that the thoracic duct had been obstructed 
by disease, and absorption by the lacteals was prevented. Hard work directly 
'after a hearty meal is bad practice. Remember the story of the two hounds. 
They were both fed alike in the morning ; one of them was taken out to run 
on a hunt, the other was tied up at home. When the master came back from 
the hunt, both dogs were killed, and their stomachs examined. It was found 
that the hound that hunted still had the stomach full of food, while that of 
the stay-at-home was empty. When you have a hard piece of work on hand, 
do not eat much; the more you eat the weaker you are for the purpose.- 
Buckland (in part). 

39. The absorbents? Lymph ? What further of the lymph ? 

40. What can you state as to the time required for digestion 7 



122 DIGESTION. 

the stomach is ordinarily empty. How much time is needed to 
complete the digestion of food, within the small intestines, is not 
certain ; but, from what we have learned respecting their xneiuoos 
of action, it must be evident that it largely depends upon ine 
amount of starch and fat which the food contains. 

41. In addition to the preparation which the food undergoes in 
cooking, which we have already considered, many circumstances 
affect the duration of digestion ; such as the quality, quantity, ana 
temperature of the food ; the condition of the mind and body ; 
sleep, exercise, and habit. Fresh food, except new bread and the 
flesh of animals recently slain, is more rapidly digested than that 
which is stale ; and animal food more rapidly than that from the 
vegetable kingdom. 

42. Food should not be taken in too concentrated a form, the 
action of the stomach being favored when it is somewhat bulky ; 
but a large quantity in the stomach, especially if there is mucn 
liquid, often retards digestion. If the white of one egg be given 
to a dog, it will be digested in an hour, but if the white of eight 
eggs be given it will not disappear in four hours. A wine-glassful 
of ice-water causes the temperature of the stomach to fall thirty 
degrees ; and it requires a half-hour before it will recover its natural 
warmth — about a hundred degrees — at which the operations of 
digestion are best conducted. A variety of articles, if not too large 
in amount, is more easily disposed of than a meal made of a single 
article; although a single indigestible article may interfere with 
the reduction of articles that are easily digested. {Read Note 6. ) 

6. Digestibility of Warm Food. — "It is very desirable that all cooked 
food should be taken hot. When it is eaten cold it reduces the temperature 
of the stomach, and both the nerves and vessels of the stomach are taxed in 
order to bring the temperature of the food thus taken up to that of the human 
body. Mankind in all ages seems to have discovered that it is desirable to pre- 
vent this tax upon the internal organs, and have taken their food hot in order 
to prevent it. It was death to the Roman slave to bring in his master's water 
tepid or cold — so much importance did they attach to hot water as drink." 
Many of our own beverages are taken hot even in summer weather ; and it 
is an economy of the vital powers to take hot meals rather than cold ones. 

41. Circumstances affecting duration of digestion ? Fresh food ? 

42. Food in concentrated form? A large quantity of food? Experiment on the deg? 
Ice-water ? Variety of articles ? 



DIGESTION. 123 

43. Strong emotion, whether of excitement or depression, checks 
digestion, as do also a bad temper, anxiety, business cares, and 
bodily fatigue. The majority of these conditions make the mouth 
dry — that is, they restrain the flow of the saliva; and without 
doubt they render the stomach dry also, by preventing the flow 
of the gastric juice. And, as a general rule, we may decide, from 
a parched and coated tongue, that the condition of the stomach is 
not very dissimilar, and that it is unfit for the performance of 
digestive labor. This is one of the points which the physician 
bears in mind when he examines the tongue of his patient. {Read 
Note 7.) 

44. The practice of eating at short intervals, or "between meals," 
as it is called, has its disadvantage, as well as rapid eating and 
over-eating, since it robs the stomach of its needed period of entire 
rest, and thus overtasks its power. With the exception of infants 
and the sick, no persons require food more frequently than once in 
four hours. Severe exercise, either directly before or directly after 
eating, retards digestion ; a period of repose is most favorable to 
the proper action of the stomach. The natural inclination to rest 
after a hearty meal may be indulged, but it should not be carried 
to the extent of sleeping ; since in that state the stomach, as well 
as the brain and the muscles, seeks release from labor. {Read Notes 
8 and 9. ) 

As a rule, hot food is better than cold, in our climate, except in very hot 
weather ; in tropical climates only can food be taken with advantage when 
cold, or ice and iced drinks be used with impunity. " — Lankester's Manual of 
Health. 

7. On the Demands of Digestion.— "The system never does two things 
well at the same time. No one can meditate a poem and drive a saw simulta- 
neously without dividing his force ; he may poetize fairly and saw poorly ; 01 
he may saw fairly and poetize poorly ; or he may both saw and poetize indif- 
ferently. Brain- work and stomach-work interfere with each other if attempted 
together. The digestion of a dinner calls force to the stomach, and tempo- 
rarily slows the brain : the experiment of trying to digest a hearty supper, and 
to sleep during the process, has sometimes cost the careless experimenter his 
life. The physiological principle is to do only one thing at a time, if you 
would do it well."— Dr. E. H. Clarke: Sex in Education. 

8. Work or Exertion. — " The best time to make great exertion is about 

43. Strong emotion ? The tongue of the patient ? 

44. Eating between meals? Severe exercise ? Sleep after meals ? 



124 



DIGESTION. 



45. The Kidneys. — Besides those already described, the abdominal 
cavity contains other important organs, viz., the kidneys and spleen. 




two hours after a meal. It is not a good 
time before breakfast, although moderate work 
may be then performed ; and those who go 
to work before breakfast should first take a 
cup of hot milk, tea, or coffee, or other sim- 
ple food. The body is weakest before breakfast. 
"Violent or rapid exertion made by chil- 
dren, and also by stout and aged people, often 
injures, and sometimes causes disease of the 
heart, when the same taken in the ordinary 
way would do no harm. Rapidly running 
up stairs, or to meet a train, sometimes causes 
death. Hence, while exercise is of the utmost 
importance to health, it should be taken in 
a regulated and rational manner, and particu- 
larly by those who have passed the period 
of youth. But disease of the heart, even in 
youth, may often be traced to indiscretion in 
Fig.29. -The Kidneys and Bladder, this particular, whether in rowing, running, 

or jumping. " — Edward Smith on Health. 
9. Tight Clothing interferes -with Digestion. — "On one wet win- 
ter's day at Florence, some years ago, I had been spending the morning in the 
studio of a sculptor of world-wide reputation. We had discussed the perfec- 
tions of female beauty, and I felt that I was sitting at the feet of a thinker, 
as well as an ' elegans formarum spectator* In the evening we met again at a 
hospitable palazzo, and, under cover of the waltz, from a quiet corner of obser- 
vation, we saw whirling by in the flesh, much that we had been thinking of 
in the marble and the clay, and our eyes could not but follow one particular 
face, famous for the assistance its great natural beauty received from art. 
'Face,' I said, but the mind of Hiram Powers was penetrating deeper, for he 
exclaimed, after a short silence : ' That is all very well, but I want to know 
where Lady puts her liver ! ' "Where, indeed ! for, calculating the circum- 
ference of the waist by the eye, allowing a minimum thickness for the walls of 
the chest, an area for the spine, oesophagus, and great blood-vessels, the sec- 
tion of the waist seemed to admit of no room for anything else. In such a 
body the liver must be squeezed down into the abdomen, stick into its hollow 
neighbors, and infringe upon all the organs. The organ which suffers most is 
the unresisting stomach, which is dragged and pushed out of all form during 
the continuance of this packing process." — Dr. T. K. Chambers on the Indi- 
ans. 

45. What are the kidneys and their functions? 



DIGESTION. 125 

The kidneys are two in number, located in the loins behind the 
intestines, one on each side of the spinal column. They are 
shaped like a bean, being about four inches long, two inches 
vide, and one inch thick. The function of the kidneys is to 
purify the blood by removing from it a poisonous substance called 
urea and certain waste products. If their action is in any way 
interfered with, blood-poisoning takes place, on account of the 
accumulation of urea, and effete materials in the system, producing 
coma, which rapidly proves fatal unless it is relieved. The watery 
fluid secreted by the kidneys is carried by two tubes, called ureters, 
to the bladder. 

46. The Spleen. — The spleen is situated on the left side of the 
abdomen behind the stomach. It is called the "milt" by the 
butcher. It has no duct, and its uses are not positively known. 
In malarial fevers, it is sometimes much enlarged, and the individual 
is said to have an "ague cake.' 

47. Effect of Alcohol upon Digestion. — "The irritating effects 
of alcohol upon the lining of the stomach * are first seen in deranged 
digestive action, in loss of appetite, and at a later stage, in changes 
in the stomach's structure, principally by a thickening of the walls 
of that organ. {Read Note io.) 

* Dyspepsia due to Alcohol — "Many cases of dyspepsia are due to 
alcohol solely and wholly, and no reliance whatever can be placed upon the 
word, statement, or assertion under oath of a drunkard ; for ' a drunkard is 
a liar.' And this holds good of both sexes, all ages, everywhere and ever."— 
Dr. J. M. Fothergill 

10. Cordials, Bitters, etc. — "In health, alcohol no wise plays a friendly 
part in regard to digestion. And it is just here that a mistake is made by 
many persons who have been deluded into the use of what are termed ' cor- 
dials' ; these are very strong alcoholic liquors, and they are supposed by those 
who use them to be especially appropriate at the end of a hearty meal. Ab- 
sinthe, the pet poison of the Parisian, is one of these falsely-named 'cordial' 
substances. These cordials are never less welcome than after a substantial 
meal. So many misleading names have been given to beverages (Cordials, 
Bitters, etc. ), that many persons have used them without knowing the evil 
consequences which follow. It is made clear by recent proofs that the so- 
called cordials are the most rapidly poisonous of all the spirituous beverages. " 



46. What is the location of the spleen ? 

47. How is the digestion affected by alcohol ? 



126 DIGESTION. 

Dr. Beaumont was able to observe the condition of the stom. 
ach of Alexis St. Martin (see. paragraph 28, page 116) after alcoholic 
excesses. He states that the surface of the organ was overcharged 
with blood, at times drops of blood exuding from it ; and that its 
secretions became thick, unnatural, and slightly tinged with blood.* 
It is a fact beyond dispute that other organs concerned in the act 
of digestion, particularly the liver, become diseased by the habitual 
use of spirituous liquors. {Read Note n.) 

48. Effects of Alcohol on the Liver. — When alcohol is taken 
into the stomach it is absorbed, and is carried by the portal vein 
directly into the liver. The blood in the liver is thus made more 
stimulating, and repeated stimulation produces over-action, which 
results in impairment or loss of power to secrete healthy bile. For 
the same reason, organic changes take place more frequently in the 
liver, from the use of alcohol, than in any other organ. It first 
becomes enlarged, owing to congestion from obstruction of the circu- 
lation and excessive growth of the connective tissue. One result 
of this overgrowth is compression and diminution in size of 
the cells which secrete the bile. Another result is a hindrance 
to the flow of blood through the liver. The organ is not only 

* Alcohol and Digestion. — "The effects of alcohol upon digestion vary 
greatly according to the quantity imbibed ; it may act as a temporary check, 
or in large doses it may completely arrest the digestive act : vomiting is fre- 
quently induced — the stomach thus freeing itself from the hurtful intruder. 
The habitual use of spirits often gives rise to a most distressing form of dys- 
pepsia. " 

11. Effect upon the Appetite. — "At a Peace Congress held at Frankfort, 
Germany, the inn-keepers found it necessary to increase the price of board of 
the strangers attending the congress, the majority of whom were teetotalers, 
for the reason that their appetites required an amount of solid food in excess 
of that usually consumed by their own nationality, who are habitual drinkers 
of beer containing appreciable amounts of alcohoL 

" By direct contact, alcohol acts upon the stomach and leads to a destruc- 
tion of its secreting tubules. Nothing with such certainty impairs the appe- 
tite and the digestive power as the continued use of strong alcoholic liquids. 
From the stomach it is absorbed, and with its distribution through the system 
it interferes with nutrition and leads to a diseased state of the liver, kidneys, 
and other organs. "—Pavy. 

48. What effect produced on the liver by alcohol? 



DIGESTION. 127 

diminished in size, but it becomes hardened and roughened — an 
appearance which has given it the name of hob-nailed liver or drunk- 
ard's liver. This condition not only interferes with the proper 
formation of bile, but it obstructs the return of blood from the 
organs in the abdomen, and we have dropsy as a consequence. 

49. The Effects of Alcohol on the Kidneys. — The action of al- 
cohol on the kidneys is similar to that which takes place in the liver. 
The first effect of repeated stimulation by alcohol is an increase of 
the natural secretions of the organs, but this continued over-action, in 
obedience to a universal law, afterward results in a diminished secre- 
tion and in injury to the substance of the kidney. "Granular 
degeneration," one of the forms of Bright's disease, takes place. 
The kidneys are unable to perform efficiently the duty of removing 
impurities from the blood ; urea, and other noxious materials accu- 
mulate, and the whole system is poisoned. 

49. How are the kidneys affected by alcohol? 



128 DIGESTION. 



QUESTIONS FOR TOPICAL REVIEW. 

PAGB 

1. What do you understand by nutrition ? 104 

2. How is the process of nutrition carried on ? 104 

3. What further can you state on the subject ? 104 

4. Describe the general plan of digestion 105 

5. How is the process of mastication carried on ? 105 

6. State what you can in relation to the formation of the teetli 106, 107 

7. What, in relation to their arrangement ? 106, 107 

8. What, in relation to the process of "shedding?" 106 

9. In relation to the different forms of teeth in different animals ?..... 108 

10. What causes operate to injure or destroy the teeth ? 109 

11. What suggestions and directions are given for the preservation of the teeth ?. . . . 109, 118 

12. What do you understand by insalivation ? 110 

13. How is the process of insalivation carried on ? 110, 111 

14. Of what importance is the saliva to the process ? Ill 

15. Of what importance are mastication and insalivation ? 112 

16. Describe the consequences of rapid eating 113 

17. What becomes of the food directly after it has undergone mastication and insali- 

vation ? 113 

18. Describe the location and formation of the stomach 113, 114 

19. Describe the process by which the gastric juice is formed '. 114, 115 

20. What are the properties and uses of the gastric juice ? 115 

21. What are the movements of the stomach, and what their uses ? 115, 116 

22. What further can you state on the subject ? 116 

23. What portions of the food are digested in the stomach ? 116, 117 

24. What are the first changes of digestion? 117 

25. What further can you state in relation to the stomach ? 117 

26. Describe the intestines 118 

27. Describe the process of intestinal digestion... 118,119 

28. What do you understand by absorption ? 119, 120 

29. How is the process of absorption effected ? 120 

30. What are the lacteals, and of what use are they ? « 121 

31. What length of time is required for the digestion of food ? 121, 122 

32. What circumstances, of food, affect digestion ? 122 

33. What circumstances, of emotion, affect digestion ? 123 

34. What suggestions and directions are given upon the subject of eating and drinking?. 123 

35. Describe the kidneys and their office 124, 125 

36. What happens when their action ceases ? 125 

37. Give the location of the spleen. Has it a duct? 125 

38. How does alcohol affect digestion ? 125 

39. Give the experiment on St. Martin 126 

40. State the effects of alcohol upon the liver 126 

41. State the effects upon the kidneys 127 



CHAPTER VII. 

The Circulation. 

The Blood — Its Plasma and Corpuscles — Coagulation of the Blood — The Uses of 
the Blood — Transfusion — Change of Color — The Organs of the Circulation 
'-The Heart, Arteries, and Veins — The Cavities and Valves of the Heart 
—Its Vital Energy — Passage of the Blood through the Heart — The fre- 
queroey and Activity of its Movements — The Pulse — The Spygmograph — • 
The Capillary Blood-vessels — The Rate of the Circulation — Assimilation — 
Injuries to the Blood-vessels — Effects of Alcohol on Heart. 

1. The Blood. — Every living organism of the higher sort, 
whether animal or vegetable, requires for the maintenance of life 
and activity, a circulatory fluid, by which nutriment is distributed 
to all its parts. In plants, this fluid is the sap ; in insects, it is a 
watery and colorless blood ; in reptiles and fishes, xc is red but cold 
blood ; while in the nobler animals and man, it is red and warm 
blood. 

2. The blood is the most important, as it is the most abundant, 
fluid of the body ; and upon its presence, under certain definite 
conditions, life depends. On this account it is frequently, and very 
properly, termed "the vital fluid." The importance of the blood, 
as essential to life, was recognized in the earliest writings. In the 
narration of the death of the murdered Abel, it is written, " the 
voice of his blood crieth from the ground." In the Mosaic law, 
proclaimed over thirty centuries ago, the Israelites were forbidden 
to eat food that contained blood, for the reason that " the life of the 
flesh is in the blood." With the exception of a few tissues, such 
as the hair, the nails, and the cornea of the eye, blood everywhere 
pervades the body, as may be proved by puncturing any part with 

1. What is required by every living organism ? In plants? Insects? Reptiles? Man? 

2. Importance and abundance of blood ? Dependence of life ? Abel? Mosaic law? In 
what part of the body is blood not found ? Quantity of blood in the body? 



130 THE CIRCULATION. 

a needle. The total quantity of blood in the body is estimated at 
about one-eighth of its weight, or eighteen pounds. 

3. The color of the blood, in man and the higher animals, as is 
well known, is red ; but it varies from a bright scarlet to a dark 
purple, according to the part whence it is taken. " Blood is thicker 
than water," as the adage truly states, and has a glutinous quality. 
It has a faint odor, resembling that peculiar to the animal from 
which it is taken. 

* 4. When examined under the microscope, the blood no longer 
appears a simple fluid, and its color is no longer red. It is then 
seen to be made up of two distinct parts : first, a clear, colorless 
fluid, called the plasma ; and, secondly, of a multitude of minute 
solid bodies, or corpuscles, that float in the watery plasma. The 
plasma, or nutritive liquid, is composed of water richly charged with 
materials derived from the food, viz., albumen, which gives it 
smoothness and swift motion; fibrin; certain fats; traces of sugar; 
and various salts. 

5. The Blood Corpuscles.— In man, these remarkable "little 
bodies," as the meaning of the word corpuscles signifies, are of a 

yellow color, but by their vast num- 
bers impart a red hue to the blood. 
They are very small, having a diametei 
of about -g^-Q-jy of an inch, and being 
one-fourth of that fraction in thick- 
ness ; so that if 3,500 of them were 
placed in line, side by side, they 
would only extend one inch; or, if 
piled one above another, it would 
take at least 14,000 of them to stand 

Fig. 30.-— The Blood Corpuscles, m . 

highly magnified. an inch high. Although so small m 

size they are very regular in form. As seen under the microscope, 
they are not globular or spherical, but flat, circular, and disc-like, 
with central depressions on each side, somewhat like a pearl button 
that has not been perforated. In freshly-drawn blood they show a 
disposition to arrange themselves in little rolls like coins (Fig. 30). 

3. Color of blood ? Its consistence ? Odor ? 

4. What is stated of the blood as viewed under the microscope? 
6. State what you can of the. Uttte bodies called corpuscles. 



R^oSSij 


Es^Wfc?J| 


r# ^IV 3 3 


■l^^ll 


Ks^b^M i9 



THE CIRCULATION. 



131 



% 




6. The size and shape of the blood corpuscles vary in different 
animals, so that it is possible to discriminate between those of man 
and the lower animals (Fig. 31). This is a point of considerable 
practical importance. For example, it is some- 
times desirable to decide in a court of justice 
the source, whether from man or an inferior 
animal, of blood stains upon the clothing of 
an accused person, or upon some deadly weapon. 
This may be done by a microscopical examina- 
tion of a minute portion of the dried stain, 
previously refreshed by means of gum-water. 
Certain celebrated cases are recorded in which 
the guilt of criminals has been established, and 
they have been condemned and punished upon 
the evidence which science rendered on this 
single point, the detecting of the human from 
other blood. 

7. The character of the blood of dead, ex- 
tinct, and even fossil animals, such as the 
mastodon, has been ascertained by obtaining 
and examining traces of it which had been shut 
up, perhaps for ages, in the circulatory canals 
of bone. A means of detecting blood in minute quantities is found 
in the spectroscope, the same instrument by which the constitution 
of the heavenly bodies has been studied. If a solution containing 
not more than one one-thousandth part of a grain of the coloring 
matter of the corpuscle be examined, this instrument will detect it. 
8. The corpuscles just described are known as the red-blood 
corpuscles. Besides these, and floating along in the same plasma, 
are the white corpuscles. These are fewer in number, but larger 
and globular in form. They are colorless, and their motion is less 
rapid than that of the other variety. The total number of both 
varieties of these little bodies in the blood is enormous. It is cal- 
culated that in a cubic inch of that fluid there are eighty-three 



Fig. 31. 

a, Oval Corpuscles of a 
fowl, b, Corpuscles of 
a frog, c, Those of a 
shark. 

The five small ones at 
the upper part of the 
figure, represent the hu- 
man corpuscles magnified 
four hundred times. 



6. The size and shape of the corpuscles? Why is the fact important? 

7. The character of the blood of dead animals ? Means of detecting such biood X 

8. White corpuscles? Total number of corpuscles in the body? 



132 THE CIKCULATION. 

millions, and at least five hundred times that number in the whole 
body. {Read Note i. ) 

9. Coagulation. — The blood, in its natural condition in the 
body, remains perfectly fluid ; but within a few minutes after its 
removal from its proper vessels, a change takes place. It begins to 
coagidate, or assume a semi-solid consistence. If allowed to stand, 
after several hours it separates into two distinct parts, one of them 
being a dark red jelly, called the coagulum, or clot, which is heavy 
and sinks; and the other, a clear, straw-colored liquid, called serum, 
which covers the clot. This change is dependent upon the presence 
in the blood of fibrin, which possesses the property of solidify- 
ing under certain circumstances, one of them being the separation 
of the blood from living tissues. The "fcolor of the clot is due to the 
entanglement of the corpuscles with the fibrin, 

10. In this law of the coagulation of the blood is our safeguard 
against death by hemorrhage, or undue loss of blood. If coagidation 
were impossible, the slightest injury in drawing blood would prove 
fatal. Whereas now, in many cases, bleeding ceases spontaneously, 
because the blood, as it coagulates, stops the mouths of the injured 
blood-vessels. In another class of cases, where larger vessels are 
cut or torn, it is ordinarily sufficient to close them by a temporary 

1, The Blood — " You feel quite sure that blood is red, do you not ? Well, 
it is no more red than the water of a stream would be if you were to fill it with 
little red fishes. Suppose the fishes to be very, very small — as small as a grain 
of sand — and closely crowded together through the whole depth of the stream, 
the water would look red, would it not ? And this is the way in which the 
blood looks red : only observe one thing — a grain of sand is a mountain in 
comparison with the little, red bodies that float in the blood, which we have 
likened to little fishes. If I were to tell you they measured about the 3200th 
part of an inch in diameter, you would not be much the wiser ; but if I tell 
you that in a single drop of blood, such as might hang on the point of a 
needle, there are a million of these bodies, you will perceive that they are both 
very minute and very numerous. Not that any one has ever counted them, 
as you may suppose, but this is as close an estimate as can be made in view of 
what is known of their minute size. " — Mace's History of a Mouthful of Bread. 



9. The blood in its natural condition in the body ? Describe the process by which the 
coagulation of blood takes place ? 
1§. If coagulation were impossible ? How is it in fact? 



THE CIRCULATION. 



133 



pressure ; for in a few minutes the clot will form and seal them up. 
In still more serious cases, where the blood-vessel is of large size, 
the surgeon is obliged to tie a ligature about it, thus preventing the 
force of the blood-current from washing away the clots, wirier^ 
forming within and around the vessel, close it effectually. 

II. It is worthy of remark that this peculiarity is early implanted 
in the blood, even before birth, and in advance of any existing 
necessity for it— thus anticipating and guarding against danger. But 
this is not alL Of most of the inferior animals, which, as compared 
with man, are quite helpless, the blood coagulates more rapidly, 
and in the case of the birds, almost instantly. The relative com- 
position of fluid and coagulated blood may be thus represented : 



Fluid Blood. 



Coagulated Blood. 




12. The Uses of the Blood. — The blood is the great provider 
and purifier of the body. It both carries new materials to all the 
tissues, and removes the worn-out particles of matter. This is 
effected by the plasma. It both conveys oxygen and removes car- 
bonic acid. This is done through the corpuscles. Some singular 
experiments have been tried to illustrate the life-giving power of 
the blood. An animal that has bled so freely as to be at the point 
of death, is promptly brought back to life by an operation called 
transfusion, by which fresh blood from a living animal is injected 
into the blood-vessels of his body. {Read Note 2.) 



2. The Work of the Blood.—" The blood, which is our life, is a complex 
fluid. It contains the materials out of which the tissues are made, and also 
the debris which results from the destruction of the same tissues, — the worn- 
out cells of brain and muscle,— the cast-off clothes of emotion, thought, and 
power. It is the common carrier, conveying unceasingly to every gland and 



11. What is worthy of remark? Coagulation of the blood of inferior animals? Of the 
blood of birds? 

12. The blood, as a provider and purifier? What uses. does the blood subserve? Experi 
ments? Transfusion? 



134 THE CIRCULATION. 

13. It is related that a dog, deaf aud feeble from age, had hearing 
and activity restored to him by the introduction into his veins of 
blood taken from a young dog ; and, that a horse, twenty-six years 
old, having received the blood of four lambs, acquired new vigor. 
And further, that a dog, just dead from an acute disease, was so far 
revived by transfusion, as to be able to stand and make a few 
movements. 

14. Transfusion jhas been practiced upon man. At one time, 
shortly after Harvey's discovery of the "Circulation of the Blood," 
it became quite a fashionable remedy, it being thought possible by 
it to- cure all forms of disease, and even to make the old young again. 
But these claims were soon found to be extravagant, and many un- 
happy accidents occurred in its practice • so that being forbidden by 
government and interdicted by the Pope, it rapidly fell into disuse. 
At the present time, however, it is sometimes resorted to in extreme 
cases, when there has been a great and rapid loss of blood ; and there 
are upon record several instances where, other means having 
failed, life has been restored or prolonged by the operation of 
transfusion. 

15. This reviving power of the blood seems to reside in the cor- 
puscles ; for transfusion, when performed with the serum alone, has, 
in every case, proved fruitless. Now, though so much depends 
upon the blood and its corpuscles, it is a mistake to suppose that in 
them alone is the seat of life, or that they are, in an exclusive 
manner, alive. All the organs and parts of the body are 
mutually dependent one upon the other, and the complete 
usefulness of any part results from the harmonious action of the 
whole. 

jrgan, the fibrin and albumen which repair their constant waste, thus supply- 
big their daily bread. Like the water flowing through the canals of Venice, 
that carries health and wealth to the portals of every house, and filth and 
Jisease from every doorway, the blood flowing through the canals of our 
organization carries nutriment to all tissues, and refuse from them." — Clarke's 
Sex in Education. 

13. The case of the deaf and feeble dog ? Horse? Dead dog ? 

14. Transfusion, as a fashionable remedy ? What further of transfusion ? 

15. The seat of the reviving power of the blood? What further is related? 



THE CIRCULATION. 135 

16. Change of Color. — The blood undergoes a variety of changes 
in its journey through the system. As it visits the different organs 
it both gives out and takes up materials. In one place it is 
enriched, in another it is impoverished. By reason of these 
alterations in its composition, the blood also changes its color. In 
one part of the body it is bright red, or arterial ; in another it is 
dark blue, or venous. In the former case it is pure, and fit for the 
support of the tissues ; in the latter, it is impure and charged with 
effete materials. (The details of the change from dark to bright 
will be given in the chapter on Respiration.) {Read Notes 3 
and 4. ) 

3. On Purifying the Blood. — " By some the blood is regarded as the 
source of all diseases, and to ' purify the blood ' is the object of their treat- 
ment. Quacks seize on this notion, and in sublime ignorance of the nature of 
the blood they profess to purify, and of the means by which their drugs could 
possibly purify it, make fortunes out of the credulity of the public. I would 
warn you against this notion of ' purifying ' the blood. The blood is not 
like a river into which anything can be introduced from without. It gets rid 
of, or destroys, all substances which intrude — all which do not form part and 
parcel of its own structure ; or, failing in that, it ceases to act as living blood. " 
— George Henry Lewes. 

4. By Means of the Blood, Exercise Benefits the Whole Body. — 
" The employment of the muscles in exercise not only benefits their especial 
structure, but it acts on the whole system. When the muscles are put in 
action, the capillary blood-vessels with which they are supplied become more 
rapidly charged with blood, and active changes take place, not only in the 
muscles, but in all the surrounding tissues. The heart is thus required to supply 
more blood, and accordingly beats more rapidly in order to supply the demand. 
A large quantity of blood is sent through the lungs, and larger supplies of 
oxygen are taken in and carried to the various tissues of the body. " The 
oxygen engenders a large amount of heat, which produces an action on the 
skin whereby the increase of heat may be got rid of. By this means the skin 
is exercised, the perspiration is poured forth, the surface is caused to glow and 
is kept in health. ' ' Not only are these organs benefited by the increased 
circulation of the blood, produced by exercise, but wherever the blood is sent, 
changes of a healthful character occur. The brain and the rest of the nervous 
system are invigorated ; the stomach has its powers of digestion improved ; 
and the liver, pancreas, and other organs perform their functions with more 
vigor." — Lankester's Manual of Health. 



16. Changes iu the blood ? What further is stated f 



136 THE CIRCULATION. 

17. Circulation. — The blood is in constant motion during life. 
From the heart, as a centre, a current is always setting toward the 
different organs ; and from these organs a current is constantly re- 
turning to the heart. In this way a ceaseless circular movement is 
kept up, which is called the Circulation of the Blood. This stream 
of the vital fluid is confined to certain fixed channels — the blood- 
vessels. Those branching from the heart are the arteries ; those con- 
verging to it are the veins. The true course of the blood was 
unknown before the beginning of the seventeenth century. In 1619 
it was discovered by the illustrious William Harvey. Like many 
other great discoverers, he suffered persecution and loss, but unlike 
some of them, he was so fortunate as to conquer and survive opposi- 
tion. He lived long enough to see his discovery universally accepted, 
and himself honored as a benefactor of mankind. 

18. The Heart. — The heart is the central engine of the circula- 
tion. In this wonderful little organ, hardly larger than a man's fist, 
resides that sleepless force by which, during the whole of life, the 
current of the blood is kept in motion. It is placed in the middle 
and front part of the chest, inclining to the left side. The heart- 
beat may be felt and heard between the fifth and sixth ribs, near 
the breast-bone. The shape of the heart is conical, with the apex 
or point downward and in front. The base, which is upward, is 
attached so as to hold it securely in its place, while the apex is 
freely movable. In order that loss of power from friction may be 
obviated, the heart is enclosed between two layers of serous mem- 
brane, which forms a kind of sac. This membrane, called the 
pericardium, is as smooth as satin, and itself secretes a fluid in 
sufficient quantities to keep it at all times well lubricated. The 
lining membrane of the heart, called the endocardium, is extremely 
delicate and smooth. {Read Note 5. ) 

5. A Poet's Summary of the Circulation : — 

" The smooth, soft air with pulse-like waves 
Flows murmuring through its hidden caves, 



17. Motion of the blood? What is meant by the circulation of the blood ? How confined? 
Discovery made by Harvey ? 

18. Office of the heart ? Location of the heart ? Its beat ? Its shape ? Protection to the 
heart ? What else is said in relation to the heart ? 



y* 



THE CIRCULATION. 137 

19. The Cavities of the Heart. — The heart is hollow, and so 
partitioned as to contain four chambers or cavities ; two at the base, 
known as the auricles, from a fancied resemblance to the ear' of a 
dog, and two at the apex or point, called ventricles. An auricle and 
a ventricle on the same side communicate with each other, but there 
is no opening from side to side. It is customary to regard the 
heart as a double organ, and to speak of its division into the right 
and left heart. For while both halves act together in point of 
time, each half sustains an entirely distinct portion of the labor of 
the circulation. The right side always carries the dark or venous 
blood, and the left always circulates the bright or arterial blood. 

20. If we examine the heart, we at once notice that, though its 
various chambers have about the same capacity, the walls of the 
ventricles are thicker and stronger than those of the auricles. This 
is a wise provision, for it is by the powerful action of the ventricles 
that the blood is forced to the most remote regions of the body. 
The auricles, on the contrary, need much less power, for they sim- 
ply discharge their contents into the ventricles below them. (Figs. 
32 and 33.) 

21. Action of the Heart. — The substance of the heart is of a 
eep red color, and its fibres resemble those of the voluntary mus- 

Whose streams of brightening purple rush, 
Fired with a new and livelier blush ; 
"While all their burden of decay 
The ebbing current steals away, 
And, red with Nature's flame, they start 
From the warm fountains of the heart. 
" No rest that throbbing slave may ask, 
Forever quivering o'er his task, 
While far and wide a crimson jet 
Leaps forth to fill the woven net, 
Which, in unnumbered crossing tides, 
The flood of burning life divides ; 
Then, kindling each decaying part, 
Creeps back to find the throbbing heart. " 

— Dr. 0. W. Holmes. 

19. Formation of the heart? Right and left heart? 

20. Capacity of the chambers of the heart? What wise provision is mentioned? The 
auricles? 

21. Substance of the heart? Its fibres? Its movements? The advantage of such move- 
ments ? Action of the heart ? Its period of repose ? 



138 



CIRCULATION. 



cles by which we move our limbs. But the heart's movements are 
entirely involuntary. The advantage of this is evident; for if it 

depended upon us to will 
each movement, our entire 
attention would be thus en- 
gaged, and we would find no 
time for study, pleasure, el- 
even sleep. The action of 
the heart consists in alter- 
nate contractions and expan- 
sions. During contraction 
the walls come forcibly to- 
gether, and thus drive out 
the blood. They then ex- 
pand and receive a renewed 
supply. These movements 
are called respectively systole 
and diastole. The latter may 
be called the heart's period 

A, Right Ventricle. E, F, Inlets to the Ventricles, of reoose ; and although it 

B, Left " G, Pulmonary Artery. *■■.■.- ~ » , 

C, Right Auricle. H, Aorta. lasts Onlv durm£ two-fifths 

D, Left Auricle. " ° 

of a heart-beat, or about a 
third of a second, yet during the day it amounts to more than 
nine hours of total rest. 

22. A remarkable property of the tissue of the heart is its in- 
tense vitality. For while it is more constantly active than any 
other organ of the body, it is the last to part with its vital energy. 
This is especially interesting in view of the fact that after life is 
apparently extinguished, as from drowning, or poisoning by chloro- 
form, there yet lingers a spark of vitality in the heart, which, by 
continued effort, may be fanned into a flame so as to revivify the 
whole body. In cold-blooded animals, this irritability of the heart 
is especially remarkable. The heart of a turtle will pulsate, and 
the blood circulate for a week after its head has been cut off; and 
its heart will throb regularly many hours after being cut out. The 




22. Remarkable property of the tissue of the heart? How shown? How interesting 
In cold-blooded animals ? Heart of a turtle ? Of a frog ? Alligator ? 



THE CIRCULATION. 139 

heart of a frog or serpent, separated entirely from the body, will 
contract at the end of ten or twelve hours ; that of an alligator has 
been known to beat twenty-eight hours after the death of the ani- 
mal. 

23. Passage of the Blood through the Heart. — Let us now 
trace the course of the blood through the several cavities of the 
heart. In the first place, the venous blood, rendered dark and im- 
pure by contact with the changing tissues of the body, returns to 
the right heart by the veins. It enters and fills the right auricle 
daring its expansion ; the auricle then contracts and fills the right 
ventricle. Almost instantly, the ventricle contracts forcibly and 
hurries the blood along the great artery of the lungs, to be purified 
in those organs. Secondly, having completed the circuit of the 
lungs, the pure and bright arterial blood enters the left auricle. 
This now contracts and fills the left ventricle, which cavity, in its 
turn, contracts and sends the blood forth on its journey again 
through the system. This general direction from right to left is 
the uniform and undeviating course of heart-currents. 

24. The mechanism which compels this regularity is as simple 
as it is beautiful. Each ventricle has two openings, an inlet and 
an outlet, each of which is guarded by strong curtains, or valves. 
These valves open freely to admit the blood entering from the right, 
but close inflexibly against its return. Thus, when the auricle 
contracts, the inlet valve opens ; but as soon as the ventricle begins 
to contract, it closes promptly. The contents are then, so to speak, 
cornered, and have but one avenue of escape — that through the out- 
let valve into the arteries beyond. As soon as the ventricle begins 
to expand again, this valve shuts tightly and obstructs the passage 
The closing of these valves occasions the two heart-sounds, which 
we hear at the front of the chest. (Figs. 35 and 36.) 

25. Frequency of the Heart's Action. — The alternation of 
contraction and expansion constitutes the heart-beats. These fol- 
low each other not only with great regularity, but with great rapid- 
ity. The average number in an adult man is about seventy-two in 

23. Course of the blood through the heart ? Course of heart-currents ? 

24. Openings of the ventricles ? How guarded ? How do the valves operate? The con- 
sequence ? Heart-sounds ? 

25. Heart-beats? The heart as a susceptible organ? Heat, exercise, etc. ? Posture? 



140 THE CIRCULATION. 

a minute. But the heart is a susceptible organ, and many circum- 
stances affect its rate of action. Heat, exercise, and food increase 
its action ; cold, fasting, and sleep diminish it. Posture, too, has a 
curious influence ; for if while sitting the beats of the heart number 
seventy-one, standing erect will increase them to eighty-one, and 
lying down will lower them to sixty-six. {Read Note 6. ) 

26. The modifying influence of mental emotions is very power- 
ful. Sudden excitement of feeling will cause the heart to palpitate, 
or throb violently. Depressing emotions sometimes temporarily 
interrupt its movements, and the person faints in consequence. 
Extremes of joy, grief, or fear have occasionally suspended the 
heart's action entirely, and thus caused death. The rate of the 
heart-beat may be naturally above or below seventy-two. Thus it 
is stated that the pulse of the savage is always slower than that of 
the civilized man. Bonaparte and Wellington were very much 
alike in their heart pulsations, which were less than fifty in the 
case of each. (Read Note 7. ) 

6. The Heart is Injured by Over-exertion. — "During exertion, if 
the heart is not oppressed, its movements, though rapid and forcible, are regu- 
lar and equal. But when it becomes embarrassed, the pulse-beats are quick, 
unequal, and at last become irregular, indicating injur}* to the organ. All 
great and sudden efforts are to be carefully avoided; excessive exercise often 
produces palpitation, and sometimes enlargement and valvular disease of the 
heart. " — Huxley. 

"No great intellectual thing was ever done by great effort; a great thing 
can only be done by a great man, and he does it without effort. The body's 
work and the head'.s Avork are to be done quietly, and comparatively without 
effort. Neither limbs or brain are ever to be strained to their utmost ; that is 
not the way in which the greatest quantity of work is to be got out of them ; 
they are never to be worked furiously, but with tranquillity and constancy. 
We are to follow the plow from sunrise to sunset, but not to pull in race- 
boats at the twilight ; we shall get no fruit of that kind of work — only disease 
of the heart. " — Ruskin. 

7. Fainting. — "When the heart suddenly ceases to a,ct, fainting or swoon- 
ing is very apt to take place. This takes place for the reason that the brain 
feels most speedily the lack of its supply of blood. Many circumstances may 
cause a faint — such as a fright, joy, excitement, the sight of blood, or the 
breathing f foul air; or it may be due to disease of the heart. In some per- 



26. Mental emotions? Sudden excitement? Excessive joy? Tie heart-beat rate? Bo- 
naparte and Wellington ? 



THE CIRCULATION. 141 

27. Activity of the Heart. — The average number of heart-beats 
during a lifetime may be considered as at the rate of seventy-two 
per minute, although this estimate is somewhat low, for during sev- 
eral years of early life the rate is above one hundred a minute. 
In one hour, then, the heart pulsates four thousand times; in a 
day, one hundred thousand times ; and in a year, nearly thirty-eight 
million times. If we compute the number during a lifetime — forty 
years being the present average longevity of civilized mankind — we 
obtain as the vast aggregate, fifteen hundred millions of pulsations. 
{Read Note %.) 

sons, fainting becomes a kind of habit; they fall into a fainting -fit on very 
slight agitation. In them the appearances are much worse than the reality, 
especially to those who are not familiar with the ailment. But persons who 
faint after exhaustion, fatigue, fasting, or anguish, require prompt attention. 
The ordinary signs are great pallor, loss of sensation, and trembling of the 
.limbs and loss of power over the muscles ; the breathing and pulse go on im- 
perfectly or stop. The first thing to do is to place the head low, thus favoring 
the supply of blood to the brain; the very act of falling is often sufficient to 
restore consciousness. Water may be sprinkled on the face, hartshorn held to 
the nose, or mustard over the heart. Pure air is a great restorative ; allow a 
current of fresh air to flow over the face, and loosen any tight bands that may 
confine the chest." — Br. J. Knight (inj^art). 

8. The Heart a Vital Machine. — "The heart is a machine. It is an 
organ constructed of muscular chambers and communicating passages, and 
supplied with mechanical contrivances, adapted to guide the stream of blood 
passing through it, and to prevent a reflux in the backward direction. Does 
not this take away wonderfully from the character of fanciful mystery with 
which poets and sentimentalists have invested it ? The heart that we have 
always heard of as the centre of the affections, the home of sensibility, the 
dwelling-place of courage, of faith, of hope, and all the rest of the virtues, is 
after all, nothing but an organ to serve for the impulsion of the blood — a mere 
force-pump, a machine. Does not this bring down our ideas, and show that 
no poetical mystery can escape the searching investigation of the anatomist ? 
Not at all. 

"For this machine that we carry about with us in our breasts is alive. 
There, at its post, at the central point of the circulation, with the soft lobes of 
the lungs folded round it like a curtain, it contracts and relaxes, and relaxes 
and contracts, with a steady and unremitting industry that by itself is some- 
thing worthy of our admiration. No other muscle in the body can do this. 
By some incomprehensible vitality of its own, it keeps up its rhythmical con- 

27. Average number of heart-beats ? In one hour? Year? Lifetime? 



142 THE CIRCULATION. 

28. Again, if we estimate the amount of blood expelled by each 
contraction of the ventricles at four ounces, then the weight of the 
blood moved during one minute will amount to eighteen pounds. 
In a day it will be about twelve tons ; in a year, four thousand 
tons ; and in the course of a lifetime over one hundred and fifty 
thousand tons. These large figures indicate, in some measure, the 
immense labor necessary to carry on the interior and vital operations 
of our bodies. In this connection, we call to mind the fanciful 
theories of the ancients in reference to the uses of the heart. They 
regarded it as the abode of the soul and the source of the nobler 
emotions — bravery, generosity, mercy, and love. The words cour- 
age and cordiality are derived from a Latin word signifying heart. 
Many other words and phrases, as hearty, heart-felt, to learn by 
heart, and large-hearted, show how tenaciousty these exploded opin- 
ions have fastened themselves upon oar language. 

29. At the present time, the tendency is to ascribe purely me- 
chanical functions to the heart. This view, like the older one, is 
inadequate ; for it expresses only a small part of our knowledge of 
this organ. The. heart is unlike a simple machine, because its mo- 
tive power is not applied from without, but resides in its own sub- 
stance. Moreover, it repairs its own waste, it lubricates its own 
action, and it modifies its movements according to the varying needs 
of the system. It is more than a mere force-pump, just as the 
stomach is something more than a crucible, and the eye something 
more than an optical instrument. ( Read Note 9. ) 

tractions without the aid of our will and even without our knowledge. While 
you are asleep and while you are awake, from the first moment of your birth, 
even from before your birth, up to the present time, it has never for one mo- 
ment stopped or flagged in its movements, for if it were to do so death would 
be the result." — Dr. J. C. Dalton. 

9. The Heart — "You all know where it is. It is the most wonderful 
little pump in the world. There is no steam-engine half so clever at its work, 
or so strong. There it is, in every one of us, beat, beating — all day and all 
night, year after year, never stopping, like a watch ticking ; only it never 
needs to be wound up, — God winds it up once for all." — Author of "Rob and 
His Friends. " 

28. Amount of blond expelled ? Theories of the ancients? 

29. The tendency at the present time ? Why is this view inadequate ? 



THE CIRCULATION. 



143 



30. The Arteries. — The tube-like canals which carry the blood 
away from the heart are the arteries. Their walls are made of 
tough, fibrous materials, so that they sustain the mighty impulse of 
the heart, and are not ruptured. In common with the heart, the 
arteries have a delicately smooth lining membrane. They are also 
elastic, and thus re-enforce the action of the heart ; they always 
remain open when cut across, and after death are usually found 
empty. 

31. The early anatomists observed this condition, and supposing 
that it existed during life, came to the conclusion that these tubes 
were designed to act as air-vessels — hence the name artery, from 
Greek words which signify " containing air." This circumstance 
affords us an illustration of the mistaken notions of the ancients in 
reference to the internal operations of the body. Cicero speaks of 
the arteries as " conveying the breath to all parts of the body." 

32. The arterial system springs from the heart by a single trunk, 
like a minute and hollow tree, with numberless branches. As 
these branches leave the heart, they divide and subdivide, continu- 
ally growing smaller and smaller, until they can no longer be traced 
by the naked eye. If, then, we continue the examination by the 
aid of a microscope, we see these small branches sending off still 
smaller ones, until all the organs of the body are penetrated by 
arteries. 

33. The Pulse. — With each contraction of the left side of the 
heart, the impulse causes a wave-like motion to traverse the entire 
arterial system. If the arteries were exposed to view, we might see 
successive waves speeding from the heart to the smallest of the 
branches, in about one-sixth part of a second. The general course 
of the arteries is as far as possible from the surface. This arrange- 
ment is certainly wise, as it renders them less liable to injury — the 
wounding of an artery being especially dangerous. It also protects 
the arteries from external and unequal pressure, by which the force 
of the heart would be counteracted and wasted. Accordingly, we 



30. What are the arteries? Their walls? Their membrane? 

31. Early anatomists? The service of the illustration ? 

32. The arterial system? The branches and sub-branches of the arteries? 

33. Successive undulations from the heart? Course of the arteries ? Protection of the 
arteries? General location of the arteries ? 



144 THE CIRCULATION, 

generally find these vessels close to the bones, or hiding behind the 
muscles and within the cavities of the body. 

34. In a few situations, however, the arteries lie near the sur- 
face ; and if we apply the finger to any of these parts, we shall dis- 
tinctly feel a throbbing motion taking place in harmony with the 
heart-beat. This is part of the wave-motion just mentioned, and is 
known as the pulse. All are familiar with the pulse at the wrist, 
in the radial artery ; but it is not peculiar to that position, for it 
may be felt in the carotid of the neck, in the temporal at the tem- 
ple, and elsewhere, especially near the joints. 

35. Since the heart-beat makes the pulse, whatever affects the 
former affects the latter also. Accordingly, the pulse is a good index 
of the state of the health, so far as the health depends upon the 
action of the heart. It informs the physician of the condition of 
the circulation in four particulars — its rate, regularity, force, and 
fullness ; and nearly every disease modifies in some respect the con- 
dition of the pulse. A very ingenious instrument, known as the 
sphygmograph, or pulse-writer, has recently been invented, by the 
aid of which the pulse is made to write upon paper its own signa- 
ture, or rather to sketch its own profile. This instrument shows 




Fig. 37.— The Form of the Pulse. 

with great accuracy the difference between the pulses of health and 
those of disease. In Fig. 37 is traced the form of the pulse in 
health, which should be read from left to right. That part of the 
trace which is nearly perpendicular coincides with the contraction 
of the ventricles, while the wavy portion marks their dilatation. 
{Read Note io.) 

10. The Beating of the Pulse. — "According to experiments made in 
Paris, the pulze of a lion beats forty times a minute ; that of a tiger, ninety- 

34. Where do the arteries lie ? If we apply the finger ? Pulse? Where felt? 

35. The pulse as an index? Of what does it inform the physician ? Instrument for re- 
cording pulsation ? 



THE CIRCULATION. 



145 



36. The Veins. — The vessels by which the blood returns to the 
heart are the veins. At first they are extremely small ; but uniting 
together as they advance, they constantly increase in size, remind- 
ing us of the way in which the fine rootlets of the plant join together 
to form the large roots, or of the rills and rivulets that flow together 
to form the large streams and rivers. In structure, the veins resem- 
ble the arteries, but their walls are comparatively inelastic. They 
are more numerous, and communicate with each other freely in 
their course, by means of interlacing branches. 

37. But the chief point of distinction is in the presence of the 
valves in the veins. These are little folds of membrane, disposed 
in such a way that they open only to receive the blood flowing 
toward the heart, and close against a current in the opposite direc- 
tion. Their position in the veins on the back of the hand may be 
readily observed, if we first obstruct the 
return of blood by a cord tied around the 
forearm or wrist. In a few minutes the 
veins will appear swollen, and upon them 
will be seen certain prominences, about an 
inch apart. These latter indicate the lo- 
cation of the valves, or, rather, they show FlG - 38. -The Valves of the 

.,.,, , . » ,/.,, i Veins highly magnified. 

that the vessels in tront ot the valves are 

distended by the blood, which cannot force a passage back through 

them. 

38. This simple experiment proves that the true direction of the 
venous blood is toward the heart. That the color of the blood is 
dark will be evident, if we compare the hand thus bound by a cord 
with the hand not so bound. It also proves that the veins lie near 
the surface, while the arteries are beneath the muscles, well pro- 




six times ; of a tapir, forty-four times ; of a horse, forty times ; of a wolf, 
forty-five times ; of a fox, forty-three times ; of a bear, thirty-eight times ; of 
a monkey, forty-eight times ; of an eagle, one hundred and sixty times. It 
was impossible to determine the beatings of the elephant's pulse. A butterfly, 
however, it was discovered, experienced sixty heart pulsations in a minute. " 



36. What are the veins ? How do they form ? What do they resemble ? 

37. Valves in the veins ? What are they ? Their position ? Experiment with the cord 1 
88. What will be proved by the experiment? What inference is drawn ? 



146 



THE CIRCULATION. 



tected from pressure; and that free communication exists from one 
vein to another. If now we test the temperature of the constricted 
member by means of a thermometer, we will find that it is colder 
than natural, although the amount of blood is larger than usual. 
From this fact we infer, that whatever impedes the venous circula- 
tion tends to diminish vitality ; and hence, articles of clothing or 
constrained postures, that confine the body or limbs, and hinder the 
circulation of the blood, are to be avoided as injurious to the health. 
39. The Capillaries. — A third set of vessels completes the list 
of the organs of circulation, namely, the capillary vessels, so called 
(from the Latin word capillaris, hair-like), because of their extreme 
fineness. They are, however, smaller than any hair, having a diam- 
eter of about g^QQ of an inch, and can only be observed by the use 
of the microscope. These vessels are the connecting link between 
the last of the arteries and the first of the veins. The existence of 
these vessels was unknown to Harvey, and was the one step want- 
ing to complete his great discovery. The capillaries were not dis- 
covered until 1661, a short time after the invention of the micro- 
scope. 





Fig. 39.— Web of a Frog's Foot, 
slightly magnified. 



Fig. 40.— Margin of Frog's Web, 
magnified thirty diameters. 



40. The circulation of the blood, as seen under the microscope, 
in the transparent web of a frog's foot, is a beautiful sight, pos- 
sessing more than ordinary interest, from the fact that something 



39. Capillaries ? How regarded ? Harvey ? 

40. The circulation of the blood in the web of a frogs foot? Describe it. How general 
Is the existence of the tissues ? 



THE CIRCULATION. 147 

much grander is taking place in our own bodies. It is like opening 
a secret page in the history of our own frames. We there see dis- 
tinctly the three classes of vessels with their moving contents ; first, 
the artery, with its torrent of blood rushing down from the heart; 
secondly, the vein, with its slow, steady stream flowing in the oppo- 
site direction ; and between them lies the network of capillaries, so 
fine that the corpuscles can pass through only " in single file." The 
current of the capillaries has here an uncertain or swaying motion, 
hurrying first in one direction, then hesitating, and turning back in 
the opposite direction, and sometimes the capillaries contract so as 
to be entirely empty. Certain of the tissues are destitute of capil- 
laries ; such are cartilage, hair, and a few others on the exterior of 
the body. In all other structures, networks of these vessels are 
spread out in countless numbers ; so abundant is the supply, that 
it is almost impossible to puncture any part with the point of a 
needle without lacerating tens, or even hundreds of these vessels. 
{Read Note n.) 

41. The capillaries are elastic, and may so expand as to pro- 
duce an effect visible to the naked eye. If a grain of sand, or 

11. Course of the Blood in the Capillaries. — " The phenomena of 
the capillary circulation are only observable with the aid of the microscope. 
It was not granted to the discoverer of the circulation to see the blood moving 
through the capillaries, and he never knew the exact mode of communication 
between the arteries and veins. After it was pretty generally acknowledged 
that the blood did pass from the arteries to the veins, it was disputed whether 
it passed in an intermediate system of vessels, or became diffused in the sub- 
stance of the tissues, like a river flowing between numberless little islands, to 
be collected by the venous radicles and conveyed to the heart. Accurate mi- 
croscopic investigations have now demonstrated the existence, and given us a 
clear idea of the anatomy of the intermediate vessels. In 1661 the celebrated 
anatomist Malpighi first saw the movement of the blood in the capillaries, in 
the lungs of a frog. This spectacle has ever since been the delight of the 
physiologist. We see the great arterial rivers, in which the blood flows with 
wonderful rapidity, branching and subdividing, until the blood is brought to 
the superb network of fine capillaries, where the corpuscles dart along one by 
one, the fluid then being collected by the veins, and carried in great currents 
to the heart." — Flint. 



41. Elasticity of the capillaries ? Grain of sand in the eye ? Blush ? Other cases ? 



-V-: 



148 THE CIRCULATION. 

some other foreign particle, lodge in the eye, it will become irritated, 
and it a short time the white of the eye will be "blood-shot." 
This appearance is due to an increase in the size of these vessels. 
A blush is another example of this, but the excitement comes 
through the nervous system, and the cause is some transient emo- 
tion, either of pleasure or pain. Another example is sometimes 
seen in purplish faces of men addicted to drinking brandy ; in them 
the condition is a congestion of the capillary circulation, and is per- 
manent, the vessels having lost their power of elastic contraction. 

42. Rapidity of the Circulation. — That the blood moves with 
great rapidity is evident from the almost instant effects of certain 
poisons, as prussic acid, which act through the blood. Experi- 
ments upon the horse, dog, and other inferior animals, have been 
made to measure its velocity. If a substance which is capable of a 
distinct chemical reaction (as potassium ferrocyanide, or barium ni- 
trate) be introduced into a vein on one side of a horse, and at the 
end of twenty or thirty- two seconds, blood be taken from a distant 
vein on the other side, its presence may be detected. In man, the 
blood moves with greater speed, and the circuit is completed in 
twenty-four seconds. 

43. What length of time is required for all the blood of the 
body to make a complete round of the circulation 1 This question 
cannot be answered with absolute accuracy, since the amount of 
the blood is subject to continual variations. But, if we assume 
this to be one-eighth of the weight of the body — about eighteen 
pounds — it will be sufficiently correct for our purpose. Now to 
complete the circuit, this blood must pass once through the left 
ventricle, the capacity of which is two ounces. Accordingly, we 
find that, under ordinary circumstances, all the blood makes one com- 
plete rotation every two minutes — passing successively through the 
heart, the capillaries of the lungs, the arteries, the capillaries of the 
extremities, and through the veins. 

44. Assimilation. — The crowning act of the circulation — the 
furnishing of supplies to the different parts of the body — is 

42. Show what time is required for a given portion of blood to travel once around the 
body. • 

43. Time required for all the blood to circulate completely around ? 

44. What is meant by assimilation ? What can you say of its use, etc. f Time ? 



THE CIRCULATION. 149 

effected by means of the capillaries. The organs have been wasted 
by use ; the blood has been enriched by the products of digestion. 
Here, within the meshes of the capillary network, the needy tissues 
and the needed nutriment are brought together. By some myste- 
rious chemistry, each tissue selects and withdraws from the blood 
the materials it requires, and converts them into a substance like 
itself. This conversion of lifeless food into living tissue is called 
assimilation. The process probably takes place at all times, but 
the period especially favorable for it is during sleep. Then the 
circulation is slower, and more regular, and most of the functions 
are at rest. The body is then like some trusty ship, which, after a 
long voyage, is "hauled up for repairs." {Read Note 12.) 

45. Injuries to the Blood-vessels. — It is important for us to 
be able to discriminate between an artery and a vein, in the case of 
a wound, and if we remember the physiology of the circulation we 
may readily do so. For, as we have already seen, hemorrhage from 
an artery is much more dangerous than that from a vein. The 
latter tends to cease spontaneously after a short time. The arterial 
blood flows away from the heart with considerable force, in jets, 
and its color is bright scarlet. The venous blood flows toward the 
heart from that side of the wound furthest from the heart, its 
stream being continuous and sluggish ; its color is dark. In an 

12. Assimilation in Repair. — ' ' Most animals have the power to repair, 
to a greater or less extent, the mutilations they undergo. In man, if the skin 
is torn off, a new skin heals over the injury, and a broken bone is caused to 
re-unite by the deposit of bone tissue between the fragments. But among the 
lower animals this power is carried to a high degree. The tail of a lizard, if 
cut off, will quickly form anew, although of a complex structure ; and spiders 
and crabs are able to develop new claws upon the stumps of broken ones. 
Observations made on salamanders, or water-lizards, show the still more 
remarkable fact that the eye and a part of the head may be entirely restored. 
Certain kinds of earth-worms can reproduce a large portion of their bodies, and 
any fragment of the hydra is able to restore itself, and become a complete 
creature after its kind. Assimilation is especially active in early years, while 
the body is growing ; for this reason, among others, the perfect health of 
children requires that they shall give a greater number of hours to sleep — 
deep, regular, and undisturbed sleep — than is needed in later life. " — Milne 
Edwards. 



45. What is stated of the injuries to the blood-vessels? 



150 THE CIRCULATION. 

injury to an artery, pressure should be made between the heart and 
the wound, while in the case of a vein that persistently bleeds, it 
should be made upon the vessel beyond its point of injury. 
{Read Note 13. ) 

46. Effects of Alcohol upon the Heart. — The first symptoms 
after a moderate dose of alcohol is an increase of the heart's action, 
a flushing of the face, a sensation of warmth within, a general glow 
without, and some other appearances of increased vitality. The 
action has been that of a spur or goad. It has caused strength to 
be expended instead of increasing it, and, in fact, costs the system 
whatever amount of force is necessary to expel it; so that there is 
a loss of strength, and not a gain. 

47. The late T)r. Parkes made a careful study of the amount of 
strain put upon the heart by alcohol. He found that it increased 
both the number and force of the heart's pulsations. The period 
of rest between the beats is reduced, and, consequently, the heart's 
nutrition must be interfered with. He estimates, in one set of ex- 
periments, that the extra work of the heart, induced by alcohol, 

13. The Varieties and Management of Hemorrhage.— "Hemor- 
rhage is the loss of blood either from an artery or a vein. When an artery is 
cut, the blood flows in jets corresponding to the beats of the heart and to the 
pulse. The jets mark that it is an artery that is wounded, and indicate that 
the pressure must be applied above the hemorrhage — that is, betwixt it and 
the heart. On the other hand, the blood returns to the heart by the veins ii» 
a steady, continuous flow. When then the hemorrhage is steady, and not in 
jets, it indicates that the bleeding is from a vein. Here the pressure must be 
applied to the limb away from the trunk, or the peripheral end of the limb, or 
below the bleeding. In addition to this, arterial blood is bright scarlet, while 
venous blood is dark and crimson. But these are matters of comparison, and 
the presence or absence of jets is the great point of distinction. 

"When then a person is wounded, a handkerchief must be bound as 
tightly as may be about the limb ; if the hemorrhage is arterial, above the 
point of issue, if venous, below it. Under any circumstances it is best to lay 
the person down quietly, especially if the bleeding is from the lower limbs. 
If they faint, let them alone in the horizontal posture." — Fothergill on the 
Maintenance of Health. 



46. How does alcohol affect the heart's action? 

47. Give Dr. Parke's experiment. 



THE CIRCULATION. 151 

was equivalent to the lifting of 1 5. 8 tons one foot daily ; and dur- 
ing two days, 24 tons in excess of the regular work. 

48. Alcohol as a Fat Producer. — Alcohol is said to diminish 
waste, and to make those "fleshy" who use it. This may well be 
the case in those — and the proportion is not small — who are ren- 
dered sluggish and sleepy by it. The fat which they acquire is the 
fat of inaction. If we may judge of the true influence of alcohol 
by experiments on the lowcsr animals, that are compelled to take it 
pure, we will not grant it any fattening power. 

49. There is a certain "fatty degeneration" in man — the result 
of alcohol-drinking — that is very disastrous, namely, a deposit of 
fat in the muscles of the body. This is destructive or weakening 
to muscular power, and when it evinces itself in the heart, it creates 
a change that is to be dreaded as sapping the strength of the one 
particular organ that should be strong in drinkers. It attacks them 
at a vital spot. The blood also undergoes a fatty change which 
greatly impairs its work of nourishing the body. 

48. How does alcohol make one fleshy ? 

49. What results? 



152 THE CIRCULATION. 

TABLE OF THE PRINCIPAL ARTERIES. 

(See Plate opposite Page 129.) 






The Head* 

Internal Carotid, J Supply the brain . 
Verte-bral, S 

Oph-thal'mic, supplies the eye. 

External Ca-rotld ( I^'ffual, supplies the tongue. 

gives off ... 1 ^^ci- 3 - 1 * supplies the lower part of the face. 

I Tem'po-ral, supplies the upper part of the head and fece 

The Trunk, 

The A or'ta, arising from the heart, is the main arterial trunk. 

Cor'o-na-ry, supplies the walls of the heart 

Bron'chi-al, supplies the lungs. 

In-ter-cos'tals, supply the walls of the chest. 

Gas'tric, supplies the stomach. 

He-pat'ic, supplies the liver. 

Splenic, supplies the spleen. 

Re'nal, supplies the kidney. 

Mes-en-terlcs, supply the bowy*. 

Spi'nal, supplies the spinal corch 



The Upper Limb. 

Branches of the Ax-il-1 



Branches of the Ax-il-la'ry, supply the shoulder. 
" " Bra'chi-al, supply the arm. 

* { supply the forearm and fingers. 

" UTaax, ) 



The Lower Limb. 

Branches of the Fem'o-ral, supply the hip and thigh. 
" " Pop-li-te'al, \ 

K c« Tlbl-al, > supply the leg and foot. 

** M Per-o-ne'al, ) 



THE CIRCULATION. 153 



QUESTIONS FOR TOPICAL REVIEW. 

PAGE 

1. In what organisms is the so-called circulatory fluid found ? 129 

2. How is it designated in the different organisms ? 129 

3. "What can you state of the importance of blood to the body ? 129, 130 

4. Of its great abundance, color, and composition ? 129,130 

5. Describe the corpuscles of the human blood 130, 131 

6. What is said of them in comparison with those of the lower animals ? 131 

7. Of the importance of sometimes detecting human from other blood ? 131 

8. What means have we of detecting blood in spots or stains? 131 

9. What is meant by coagulation of the blood?. 132 

10. What wisdom is there in the law of the blood's coagulation ? 132 

11. How is this wisdom made manifest ? 132 

12. In what cases is the aid of the surgeon required? 132, 133 

13. What are the two great uses of the blood? 133 

14. Through what mediums is the blood provided with new material and relieved of the 

oldmaterial? 133 

15. What do you understand by the operation called transfusion ? 134 

16. What cases of transfusion are reported of the lower animals ? 134 

17. What can you state of transfusion as practiced upon man ? 134 

18. What further can you say on the subject? 134 

19. What changes take place in the color of the blood in its journey through the system ? 135 

20. State all you can in relation to the circulation of the blood 136 

All, in relation to the size, shape, and location of the heart 136 

22. How is the loss of power in the heart-movements obviated ? 136 

23. Give a description of the formation of the heart...., 137 

24. What can you state of the ventricles and auricles of the heart ? 137 

25. Describe the action of the heart 137, 138 

26. What special vitality does the tissue of the heart possess ? 138 

27. State all you can on the subject 138 

28. Describe the course of the blood through the cavities of the heart 139 

29. Describe the mechanism that regulates the heart-currents 139 

30. How do you account for the two heart-sounds at the front of the chest ? 139 

31. State what you can of the frequency of the heart's action 139, 140 

32. Of the activity of the heart 141 

33. What do you understand by the arteries?. 143 

34. State what you can of the arteries and the arterial system 143 

35. What do you understand by the pulse?.... 143,144 

36. In what part of the body may the pulse be felt ? 144 

37. What further can you state of the pulse? 144 

38. Whatare the veins? 145 

39. Where do they exist, and how are they formed?. 145 

40. Describe the valves of the veins and their uses 145 

41. Now give a full description of the construction of the veins 145 

42. What further can you state of the veins?. 145, 146 

43. What do you understand by the capillaries ?. 146,147 

44. What service do the capillaries perform ? 146 

45. What can you state of the rapidity of the blood's circulation ? 14S 

46. Of the process known as assimilation ?. 149 

47. Of injuries to the blood-vessels? v 149 

48. What is the effect of alcohol upon the heart?. 150 

49. What issaid of alcohol as a fat-producer ? 151 



CHAPTER VIII. 

Respiration. 

The Objects of Respiration — The Lungs — The Air-passages — The Movements of 
Respiration — Expiration and Inspiration — Tlie Frequency of Respiration — 
Capacity of the Lungs — The Air we Breathe — Changes in the Air from 
Respiration — Changes in the Blood — Interchange of Gases in the Lungs — 
Comparison between Arterial and Venous Blood — Respiratory Labor — Im- 
purities of the A ir — Dust — Carbonic Acid — Effects of Impure Air — Nature's 
Provision for Purifying the Air — Ventilation — Animal Heat — Spontaneous 
Combustion. 

1. The Object of Respiration. — In one set of capillaries, or 

hair-like vessels, the blood is impoverished in order to support the 
different members and organs of the body. In another capillary- 
system the blood is refreshed and again made fit to sustain life. 
The former belongs to the greater or systemic circulation ; the latter 
to the lesser or pulmonary, so called from pulmo, the lungs, in which 
organs it is situated. The blood, as sent from the right side of the 
heart to the lungs, is venous, dark, impure, and of a nature hurtful 
to the tissues. But, when the blood returns from the lungs to the 
left side of the heart, it has become arterial, bright, pure, and no 
longer injurious. This marvellous purifying change is effected by 
means of the very familiar act of respiration, or breathing. 

2. The Lungs. — The lungs are the special organs of respiration. 
There are two of them, one on each side of the chest, which cavity 
they, with the heart, almost wholly fill. The lung-substance is soft, 
elastic, and sponge-like. Under pressure of the finger, it crepitates, 
or crackles, and floats when thrown into water; these properties 
being due to the presence of air in the minute air-cells of the lungs. 
To facilitate the movements necessary to these organs, each of them 

1. Difference between the two sets of capillaries? Change effected by respiration or 
breathing? 

2. What are the iungs I How many lungs are there? Lung-substance? Its properties? 
The pleura ? 



RESPIRATION. 



155 



is provided with a double covering of an exceedingly smooth and 
delicate membrane, called the pleura. One layer of the pleura is 




Fig. 41.— Organs of the Chest. 



A, Lungs. 

B, Heart. 



D, Pulmonary Artery. 

E, Trachea. 



attached to the walls of the chest, and the other to the lungs ; and 
they glide, one upon the other, with utmost freedom. Like the 
membrane which envelops the heart, the pleura secretes its own 
lubricating fluid, in quantities sufficient to keep it always moist. 

3. The Air-Passages. — The lungs communicate with the exter- 
nal air by means of certain air-tubes, the longest of which — the 
trachea, or windpipe — runs along the front of the neck (Fig. 41, E, 
and 42). Within the chest this tube is divided into two" branches, 
one entering each lung; these in turn give rise to numerous 
branches, or bronchial tubes, as they are called, which gradually 
diminish in size until they are about one twenty-fifth of an inch in 



3. Communication of the lungs with the external air? Bronchial tubes? 



156 



RESPIRATION. 



diameter. Each of these terminates in a cluster of little pouches, 
or " air-cells," having very thin walls, and covered with a capillary 
network, the most intricate in the body (Fig 43). 

4. These tubes are somewhat flexible, sufficiently so to bend 
when the parts in which they are situated move; but they are 




Fro. 42.— Larynx, Trachea, and 
Bronchial Tubes. 




Fig. 43.— Diagram and Section of 
the Air-cells. 



greatly strengthened by bands or rings of cartilage which keep the 
passages always open; otherwise there would be a constantly- 
recurring tendency to collapse after every breath. The lung-sub- 
stance essentially consists of these bronchial tubes and terminal 
air-cells, with the blood-vessels ramifying about them (Fig. 44). 
At the top of the trachea is the larynx, a sort of box of cartilage, 
across which are stretched the vocal cords. Here the voice is pro- 
duced chiefly by the passage of the respired air over these cords, 
causing them to vibrate. 

5. Over the opening of the larynx is found the epiglottis, which 
fits like the lid of a box at the entrance to the lungs, and closes 
during the act of swallowing, so that food and drink shall pass 



4. Office of the bronchial tube* ? What further can you state of them ? 

5. The epiglottis? When it does not close in time, what is the consequence? 



RESPIRATION. 



157 



backward to the oesophagus, or gullet (Fig. 45). Occasionally it 
does not close in time, and some substance intrudes within the 
larynx, when we at once discover, by a choking sensation, that 




"something has gone the wrong way," and, by coughing, we 
attempt to expel the unwelcome intruder. The epiglottis is one of 
the many safeguards furnished by nature for our security and com- 
fort, and is planned and put in place long before these organs are 
brought into actual use in breathing and in taking food. 

6. The air-passages are lined throughout almost their whole ex- 
tent with mucous membrane, which keeps them in a constantly 
moist condition. This membrane has cells of a peculiar kind upon 
its outer surface. If examined under a powerful microscope, we may 
see, even for a considerable time after their removal from the body, 
that these cells have minute hair-like processes in motion, which 
wave like a field of grain under the influence of a breeze (Fig. 46). 
This is a truly beautiful sight ; and since it is found that these 
little cilia, as they are called, always produce currents in one 

6. Lining of the air-passages? Ciliated cells ? Their uses? The three diseases of the 
lungs? 



158 



RESPIRATION. 



direction — from within outward — it is probable that they serve a 
useful purpose in catching and carrying away from the lungs dust 
and other small particles drawn in with the breath (Fig. 46). The 




Fig. 45.— Section of the Mouth and Throat, 

A, The Tongue. C, Vocal Cord. N, Trachea. 

B, The Uvula. E, Epiglottis. O, ffisophagus. 

L, Larynx. 

three diseases which more commonly affect the lungs, as the result 
of exposure, are pneumonia, or inflammation of the lungs, affecting, 
principally, the air-cells ; bronchitis, an inflammation of the large 
bronchial tubes ; and pleurisy, an inflammation of the pleura, or 
outside wrapping of the lungs. Among the young, an inflamma- 
tion of the trachea takes place, known as croup. 

7. The Movements of Respiration. — The act of breathing has 

7. The act of breathing ? Extension of the chest by breathing ? 



RESPIRATION. 



159 







Fig. 



-Ciliated Cells highly 
magnified. 



two parts — (1), inspiration, or drawing air into the lungs, and (2), 
expiration, or driving it out again. In inspiration, the chest ex- 
tends in its length, breadth, and height. The motion outward and 
upward can be observed every time we 
draw a full breath ; and is caused by 
a lifting of the ribs. But the motion 
downward is not so apparent, as it is 
caused by a muscle within the body 
called the diaphragm. This is the thin 
partition which separates the chest from 
the abdomen, rising like a dome within 
the chest (Fig. 20). 

8. With every inspiration the diaphragm contracts, and in so 
doing, approaches more nearly a level surface, and thus enlarges the 
capacity of the chest. Laughing, sobbing, and sneezing are due to 
sudden action of the diaphragm. On the proper acting of this 
muscle depends our power to breathe deeply; and like other 
muscles, its strength is increased by exercise. This gives that 
endurance, or " long wind," as it is commonly called, which is 
possessed in a marked degree by the mountaineer, the oarsman, and 
the trained singer. The habit of taking frequent and deep inspira- 
tions, in the erect position, with the shoulders thrown back, tends 
greatly to increase the capacity and. power of the organs of 
respiration. 

9. Expiration is a less powerful act than inspiration. The dia- 
phragm relaxes, and ascends in the form of a dome ; the ribs descend 
and contract the chest ; while the lungs themselves, being elastic, 
assist to drive out the air. The latter passes out through the same 
channels by which it entered. At the end of each expiration 
there is a period of repose, lasting about as long as the period of 
action. 

10. Frequency of Respiration. — It is usually estimated that we 
breathe once during every four beats of the heart, or about eighteen 
times in a minute. There is, of course, a close relation between the 



8. Contraction of the diaphragm? Power of the diaphragm? Effects of extending the 
walls of the chest ? The habit of taking frequent and deep inspirations ? 

9. Expiration? The mechanism of expiration? 

10. Frequency of respiration ? Eifect of hurried actiou of the heart ? 



160 RESPIRATION. 

heart and lungs, and whatever modifies the pulse, in like man 
ner affects the breathing. When the action of the heart is hurried, 
a larger amount of blood is sent to the lungs, and, as a consequence, 
they must act more rapidly. Occasionally, the heart beats so very 
forcibly that the lungs cannot keep pace with it, and then we ex- 
perience a peculiar sense of distress from the want of air. Tins 
takes place when we run until we are " out of breath." At the end 
of every fifth or sixth breath, the inspiration is generally longer 
than usual, the effect being to change more completely the air of the 
lungs. 

11. Although, as a general rule, the work of respiration goes on 
unconsciously and without exertion on our part, it is, nevertheless, 
under the control of the wilL We can increase or diminish the 
frequency of its acts at pleasure, and we can " hold the breath," or 
arrest it altogether for a short time. From twenty to thirty seconds 
is ordinarily the longest period in which the breath can be held ; 
but if we first expel all the impure air from the lungs, by taking 
several very deep inspirations, the time may be extended to one cind a 
half or even two minutes. This should be remembered, and acted 
upon, before passing through a burning building, or any place whera 
the air is very fouL The arrest of the respiration may be still 
further prolonged by training and habit. It is said that the pearl- 
fishers of India can remain three or four minutes under water with- 
out being compelled to breathe. 

12. Capacity of the Lungs. — The lungs are not filled and 
emptied by each respiration. For while their full capacity, in the 
adult, is three hundred and twenty cubic inches, or more than a 
gallon, the ordinary breathing air is only one-sixteenth part of that 
volume, or twenty cubic inches — being two-thirds of a pint. 
Accordingly, a complete renovation, or rotation, of the air of the 
lungs does not take place more frequently than about once a minute ; 
and by the gradual introduction of the external air, its temperature 
is considerably elevated before it reaches the delicate capillaries that 
surround the air-cells. In tranquil respiration, less than two-thirds 



11. Respiration controlled by the will ? Advantage of the knowledge to us ? 

12. Capacity of the lungs ? Time required to renovate the air in the lungs? In tranquil 
respiration ? Importance of the provision ? 



RESPIRATION. 161 

of the breathing power is called into exercise, leaving a reserve 
capacity of about one hundred and twenty cubic inches, equivalent 
to three and one-half pints. This provision is indispensable to the 
continuation of life ; otherwise, a slight interference with respira- 
tion — by an ordinary cold, for instance — would suffice to cut off the 
necessary air, and the spark of life would be speedily extinguished. 
13. The Air we Breathe. — The earth is enveloped on all sides 
by an invisible fluid, called the atmosphere. It forms a vast ocean 
of air, forty-five miles deep, encircling and pervading all objects on 
the earth's surface, and is absolutely essential for the preservation 
of all vegetable and animal life — in the sea, as well as on the land 
and in the air. At the bottom, or in the lower strata of this ocean 
of air, we move and have our being. Perfectly pure water will not 
support marine life, for a fish may be drowned in water from which 
the air has been exhausted, just as certainly as a mouse, or any 
other land animal will perish if held under water for a short time. 
The cause is the same in both cases — the animal is deprived of 
the requisite amount of air. It is also stated, that if the water- 
supply of the plant be deprived of air, its growth is checked. 
{Read Note I.) 

1. The Atmosphere. — " It surrounds us on all sides, yet we see it not ; 

it presses on us with a load of fifteen pounds to every square inch of surface of 
our bodies, or from seventy to one hundred tons on us in all, yet we do not so 
much as feel its weight. Softer than the softest down — more impalpable than 
the finest gossamer — it leaves the cobweb undisturbed, and scarcely stirs the 
lightest flower that feeds on the dew it supplies ; yet it bears the fleets of 
nations on its wings around the world, and crushes the most refractory sub- 
stances beneath its weight. When in motion, its force is sufficient to level the 
most stately forests with the earth ; to raise the waters of the ocean into 
ridges like mountains, and dash the strongest ships to pieces like toys. It 
bends the rays of the sun from their path, to give us the twilight of evening 
and of dawn ; it disperses and refracts their various tints, to beautify the ap- 
proach and retreat of the orb of day. But for the atmosphere, sunshine would 
burst on us and fail us at once, and at once remove us from midnight darkness 
to the blaze of noon. We should have no twilight to soften and beautify the 
landscape, no clouds to shade us from the scorching heat ; but the bald earth, 
as it revolved on its axis, would turn its tanned and weakened front to the full 
and unmitigated rays of the lord of day." — Buish. 

13. The atmosphere ? How high or deep ? How essential to life ? Marine life in per- 
fectly pure water and air? 



-4 — 15 

\once 



162 RESPIRATION. 

14. The air is not a simple element, as the ancients supposed, 
but is formed by the mingling of two gases, known to the chemist 
as oxygen and nitrogen, in the proportion of one part of the former 
to four parts of the latter, These gases are very unlike, being 
almost opposite in their properties : nitrogen is weak, inert, and 
cannot support life; while oxygen is powerful, and incessantly 
active, and is the essential element which gives to the atmosphere 
its power to support life and combustion. The discovery of this 
fact was made by the French chemist, Lavoisier, in 1778. 

. Changes in the Air from Respiration. — Air that has been 
once breathed is no longer fit for respiration. An animal confined 
within it will soon die ; so, also, a lighted candle placed in it will 
be at once extinguished. If we collect a quantity of expired air 
and analyze it, we shall find that its composition is not the same as 
that of the inspired air. T\ men the air entered the lungs it was 
rich in oxygen ; now it contains twenty-five per cent, less of that 
gas. Its volume, however, remains nearly the same — its loss being 
made up by another and very different gas, which the lungs exhale, 
palled carbonic acid, or, as the chemist terms it, carbonic dioxide. 

16. The expired air has also gained moisture. This is noticed 
when we breathe upon a mirror or the window-pane, the surface 
being tarnished by the condensation of the watery vapor given off 
by the lungs. In cold weather, this causes the fine cloud which is 
seen issuing from the nostrils or mouth with, each expiration, and 
contributes in forming the feathery crystals of ice which decorate 
our window-panes on a winter's morning. 

17. This watery vapor contains a variable quantity of animal 
matter, the exact nature of which is unknown ; but when collected 
it speedily putrefies and becomes highly offensive. From the effects, 
upon small animals, of confinement in their own exhalations, having 
at the same time an abundant supply of fresh air, it is believed that 
the organic matters thrown off by the lungs and skin are direct and 
active poisons ; and that to such emanations from the body, more 



14. Composition of the air? Properties of the two gases ? 

15. Air once breathed? An animal in it ? A candle? Analysis of expired air ? Change 
to volume ? 

16. What else has the expired air gained ? When and where noticed? 

17. Nature of the watery vapor? Its effects upon animals? 



RESPIRATION. 163 

than to any other cause, are due the depressing and even fatal re- 
sults which follow the crowding of large numbers of persons into 
places of limited capacity. {Read Note 2.) 

18. History furnishes many painful instances of the ill effects of 
overcrowding. In 1756, of one hundred and forty-six Englishmen 
imprisoned in the Black Hole of Calcutta, only twenty-three, at the 
end of eight hours, survived. After the battle of Austerlitz, three 
hundred prisoners were crowded into a cavern, where, in a few 
hours, two-thirds of their number died. On board a steamship, 
during a stormy night, one hundred and fifty passengers were con- 

2. The Two Breaths — "Every time you breathe, you breathe two dif- 
ferent breaths : you take in one, you give out another. The composition of 
those two breaths is different. Their effects are different. The breath which 
has been breathed out must not be breathed in again. To tell you why it 
must not would lead me into anatomical details, not quite in place here as yet ; 
but this I may say : those who habitually take in fresh breath will probably 
grow up large, strong, ruddy, cheerful, active, clear-headed — fit for their work. 
Those who habitually take in the breath which has been breathed out by them- 
selves, or any other living creature, will certainly grow up — if they grow up at 
all — small, weak, pale, nervous, depressed, unfit for work, and tempted contin- 
ually to resort to stimulants and become drunkards. 

"If you want to see how different the breath breathed out is from the 
breath taken in, you have only to try a somewhat cruel experiment, but one 
which people too often try upon themselves, their children, and their work- 
people. If you take any small animal with lungs like your own — a mouse, for 
instance — and force it to breathe no air but what you have breathed already ; 
if you put it in a close box, and, while you take in breath from the outer air, 
send out your breath through a tube into that box, the animal will soon faint ; 
if you go on long with this process, he will die. * * * * What becomes of 
this breath which passes from your lips ? Is it merely harmful, merely waste ? 
God forbid ! God has forbidden that anything should be merely harmful or 
merely waste in this so wise and well-made world. The carbonic acid which 
passes from your lips at every breath is a precious boon to thousands of things 
of which you have daily need. For though you must not breathe your breath 
again, you may at least eat your breath, if you will allow the sun to transmute 
it for you into vegetables ; or you may enjoy its fragrance and its color in the 
shape of a lily or a rose. When you walk in a sunlit garden, every word you 
speak, every breath you breathe, is feeding the plants and flowers around."— 
Rev. Charles Kingsley on the Two Breaths. 



18. Give some of the instances furnished by history. 



164 RESPIRATION. 

fined in a small cabin, but when morning came, only eighty remained 
alive. 

19. Changes in the Blood from Respiration. — The most strik- 
ing change which the blood undergoes by its passage through the 
lungs, is the change of color from a dark blue to bright red. That 
this change is dependent upon respiration has been fully proved by 
experiment. If the trachea, or windpipe, of a living animal be so 
compressed as to exclude the air from the lungs, the blood in the 
arteries will gradually grow darker, until its color is the same as 
that of the venous blood. When the pressure is removed, the 
blood speedily resumes its bright hue. Again, if an animal breathes 
an atmosphere containing more oxygen than atmospheric air, the 
color changes from scarlet to vermilion, and becomes even brighter 
than arterial blood. This change of color is not of itself a very 
important matter, but it indicates a most important change of com- 
position. 

20. The air, as we have seen, by respiration loses oxygen and 
gains carbonic acid : the blood, on the contrary, gains oxygen and 
loses carbonic acid. Oxygen is the food of the blood corpuscles ; 
while the articles we eat and drink go more directly to the plasma 
of the blood. The air, then, it is plain, is a sort of food, and we 
should undoubtedly so regard it, if it were not for the fact that we 
require it constantly, instead of taking it at stated intervals, as is 
the case with our articles of diet. Again, as the demand of the 
system for food is expressed by the sensation of hunger, so the de- 
mand for air is marked by a painful sensation called suffocation. 

21. Interchange of Gases in the Lungs. — But the air and the 
blood are not in contact, as they are separated from each other by 
the walls of the air-cells and of the blood-vessels. How then do 
the two gases, oxygen and carbonic acid, exchange places ? Moist 
animal membranes have a property which enables them to transmit 
gases through their substance, although they are impervious to 
liquids. This may be beautifully shown by suspending a bladder 
containing dark venous blood in a jar of oxygen. At the end of a 

19. Change in the blood from blue to red. Upon what does the change depend? How 
shown ? 

20. What does the air lose and gain by respiration ? What, the blood ? Air as food ? 

21. Moist animal membranes? How shown with the bladder? 



RESPIRATION. 165 

few hours the oxygen will have diminished, the blood will he 
brighter in color, and carbonic acid will be found in the jar. 

22. If this interchange take place outside of the body, it must 
take place more perfectly within it, where it is favored by many 
additional circumstances. The walls of the vessels and the air-cells 
offer no obstacle to this process, which is known as gaseous diffusion. 
Both parts of this process of exchange are equally important. With- 
out oxygen life ceases ; if carbonic acid is not thrown off, it acts 
like a poison, producing unconsciousness, convulsions, and death. 

23. Difference between Arterial and Venous Blood.— The 
following table presents the essential points of difference in the ap- 
pearance and composition of the blood, before and after its passage 
through the lungs : 

Venous Blood. Arterial Blood. 

Color, Dark blue, Scarlet. 

Oxygen, 8 per cent, 18 per cent. 

Carbonic Acid, 15 to 20 per cent, 6 per cent, or less. 

"Water, More. Less. 

The temperature of the blood varies considerably ; but the arterial 
stream is generally warmer than the venous. The blood imparts 
heat to the air while passing through the lungs, and consequently 
the contents of the right side of the heart have a higher tempera- 
ture than the contents of the left side.* 

24. By means of the spectroscope, we learn that the change of 
color in the blood has its seat in the corpuscles ; and that, accord- 
ing as they retain oxygen, or release it, they present the spectrum of 
arterial or of venous blood. There evidently exists, on the part of 
these little bodies, an affinity for this gas, and hence they have 
been called " carriers of oxygen." It was long ago thought that 
blue blood was peculiar to persons of princely or royal descent, and 
boastful allusions to the " sang azure " of kings and nobles are quite 
often met with. Physiology, however, informs us that blue blood 
flows in the veins of all — the low as well as the high — and that so 
far from being a mark of purity, it really indicates waste and decay. 

* " Bernard has succeeded in establishing the following facts with regard to the tempera- 
ture (of the blood) in various parts of the circulatory system in dogs and sheep: 1. The 
blood is warmer in the right than in the left cavities of the heart. 2. It is warmer in the 
arteries than in the veins, with a few exceptions."— Physiology of Man, Flint. 

22. Gaseous diffusion? If oxygen be not received ? If carbonic acid be retained ? 

23. Difference in the appearance and composition of the blood? Temperature of the 
blood ? The blood while passing through the lungs? The consequence ? 

24. What do we learn by means of the spectroscope? "Carriers of oxygen"? Blue 
blood in the system ? 



166 RESPIRATION. 

25. Amount of Respiratory Labor. — During ordinary calm 
respiration, we breathe eighteen times in a minute; and twenty 
cubic inches of air pass in and out of the lungs with every breath. 
This is equivalent to the use of three hundred and sixty cubic 
inches, or more than ten pints of air each minute. From this we 
calculate that the quantity of air which hourly traverses the lungs 
is about thirteen cubic feet, or seventy-eight gallons ; and daily, not 
less than three hundred cubic feet, an amount nearly equal to the 
contents of sixty barrels. 

26. Of this large volume of air five per cent, is absorbed in its 
transit through the lunGfs. The loss thus sustained is almost 
wholly of oxygen, and amounts to fifteen cubic feet daily. The 
quantity of carbonic acid exhaled by the lungs during the day is 
somewhat less, being twelve cubic feet. Under the influence of 
excitement or exertion, the breathing becomes more frequent and 
more profound; and then the internal respiratory work increases pro- 
portionately, and may even be double that of the above estimate. 
It has been estimated that in drawing a full breath, a man exerts a 
muscular force equal to raising two hundred pounds placed upon 
the chest. 

27. Impurities of the Air. — The oxygen in the atmosphere is 
of such prime importance, and its proportion is so nicely adjusted 
to the wants of man, that any gas or volatile substance which sup- 
plants it must be regarded as a hurtful impurity. All gases, how- 
ever, are not alike injurious. Some, if inhaled, are necessarily 
fatal ; arsenuretted hydrogen being one of these, a single bubble of 
which destroyed the life of its discoverer, Gehlen. Others are not 
directly dangerous, but because they take the place of oxygen, and 
exclude it from the lungs, they do harm, and become dangerous. 
To this latter class belongs carbonic acid. 

28. J lost of the actively poisonous gases have a pungent or 
offensive odor ; and, as may be inferred, most repugnant odors indi- 
cate the presence of substances unfit for respiration. Accordingly, 
as we cannot see or taste these impurities, the sense of smell is our 

25. The amount of air that passes in and out of the lungs ? 

26. Air absorbed in its transit through the lungs? The loss? Carbonic acid exhaled? 
Effect of excitement or exertion ? What estimate ? 

27. Importance of the oxygen in the atmosphere ? Injurious character of gases? 
2S. Pungency of gases ? The inference ? Our safeguard ? 



RESPIRATION. 167 

principal safeguard against them. In this we recognize the fore- 
thought which has stationed this sense, like a sentinel, at the propel 
entrance of the air-passages, to give us warning of approaching 
harm. Take, as an example, the ordinary illuminating gas of 
cities, from which so many accidents happen. How many more 
deaths would it cause if, when a leak occurs, we were not ahle ta 
discover the escape of the gas hy means of its disagreeable odor 
{Read Notes 3 and 4. ) 

29. Organic matters exist in increased measure in the expired 
breath of sick persons, and impart to it, at times, a putrid odor. 
This is especially true in diseases which, like typhus and scarlet 
fever, are referable to a blood poison. In such cases the breath is 
one of the means by which nature seeks to expel the offending 
material from the system. Hence, those who visit or nurse fever- 
sick persons should obey the oft-repeated direction, " not to take 
the breath of the sick." At such times, if ever, fresh air is 
demanded, not alone for the sick, but also for those who take care 
of them (See Care of Sick-Eoom, Appendix). 

3. Cleanliness the Sum Total of Hygiene. — "Disinfectants have 
the power of destroying the cause, and of arresting the spread of most epi- 
demics and contagious diseases, but cleanliness is the best preventive of 
disease. "Whenever practicable, the abundant use of water is better than 
disinfection. 'Let no one ever depend upon disinfectants, fumigations, and 
the like, for purifying the air. The offensive thing, not its smell, must 
be removed.' " — Florence Nightingale, Notes on Nursing {in part). 

4. The True Prevention of Epidemics. — "It was in England that 
solution of the great problem of hygiene was first attempted. ' Preventive 
Medicine,' it is there called. Palmerston told a deputation which waited on 
him in order to ask him to order a fast on the approach of the second epidemic 
of cholera, to cleanse their sewers, and diligently visit the dwellings of the poor. 
And he did not confine himself to good advice, but, with his usual energy, 
he laid his hand on sanitary legislation, and purified the air of London and 
the large manufacturing towns. The result of the sanitary measures carried 
out was a reduction of the mortality of London from 26 to 23 per 1,000, and 
in some of the towns to 17 per 1,000 — a low death-rate previously only 
equalled in the Isle of Wight. More than four thousand lives have been pre- 
served yearly in London ; and, assuming that the mortality among the sick is 
1 in 20, this number represents a diminution in yearly sickness to the extent 
of eighty thousand." — Dr. Joseph Seegen in the Vienna Medical Weekly. 

29. The air of rooms ia which fever-sick persons are confined ? 



168 RESPIRATION. 

30. Dust in the AiP. — Attention has lately been directed to the 
dust, or haze, that marks the ray of sunshine across a shaded room. 
Just as, many years ago, it was discovered that myriads of animal- 
cules were found in the water we drank, so now the microscope re- 
veals " the gay motes that dance along a sunbeam " to contain 
multitudes of animal and vegetable forms of a very low grade — the 
germs of fermentation and decay, and the probable sources of 
disease. 

31. It is found that the best filter by which to separate this float- 
ing dust from the air is cotton wool, although a handkerchief will 
imperfectly answer the same purpose. In a lecture on this subject 
by Prof. Tyndall, he remarks that, "by breathing through a cotton 
wool respirator, the noxious air of the sick-room is restored to prac- 
tical purity. Thus filtered, attendants may breathe the air un- 
harmed. In all probability, the protection of the lungs will be the 
protection of the whole system. For it is exceedingly probable 
that the germs which lodge in the air-passages are those which sow 
epidemic disease in the body. If this be so, then JLisease can cer- 
tainly be warded off by filters of cotton wool. By this means, so 
far as the germs are concerned, the air of the highest Alps may be 
brought into the chamber of the invalid." 

32. Carbonic Acid in the Air.— AVe have already spoken of 
this gas as an exhalation from the lungs, and a source of impurity ; 
but it exists naturally in the atmosphere in the proportion of one- 
half part per thousand. In volcanic regions it is poured forth in 
enormous quantities from fissures in the earth's surface. Being 
heavier than air, it sometimes settles into caves and hollows in 
the surface. It is stated that in the island of Java, there is a place 
called the " Valley of Poison," where the ground is covered with 
the bones of birds, tigers, and other wild animals, which were suffo- 
cated by carbonic acid while passing over it. The Lake Avernus, 
the fabled entrance to the infernal regions, was, as its name implies, 
birdless, because the birds, while flying over it, were poisoned by 
the gas, and fell dead into its waters. In mines, carbonic acid 



SO. Animalcules in the water? Dust in the air ? 

31. The best air filter? The remarks of Prof. Tyndall ? 

32. Carbonic acid in volcanic regions ? In Java ? At Lake Avernus ? In mines ? 



RESPIRATION, 169 

forms the dreaded choke-damp, while carbureted hydrogen is the 
fire-damp. 

33. In the open air, men seldom suffer from carbonic acid, for, 
as we shall see presently, nature provides for its rapid distribution, 
and even turns it to a good use. But its ill effects are painfully 
evident in our homes, schools, and churches, where it is liable to 
collect as the waste product of respiration, and of that combustion 
which is necessary for lighting and warming our homes. A man 
exhales, during repose, not less than one-half cubic foot of carbonic 
acid per hour. A single gas-burner liberates five cubic feet in the 
same time, therefore spoiling about as much air as ten men. A fire 
burning in a grate or stove emits some impure gases, and at the 
same time abstracts from the air as much oxygen as twelve men 
would consume in the same period, thus increasing the relative 
amount of carbonic acid in the air. From furnaces, as ordinarily 
constructed, this and other gases are constantly leaking and poison- 
ing the air of tightly-closed apartments. 

34. Effects of Impure Air. — Carbonic acid, in its pure form, is 
irrespirable, causing rapid death by suffocation. Air containing 
forty parts per thousand of this gas (the composition of the expired 
breath) extinguishes a lighted candle, and is fatal to birds ; when 
containing one hundred parts, it no longer yields oxygen to man and 
other warm-blooded animals, and is, of course, speedily fatal to 
them. In smaller quantities, this gas causes headache, labored res- 
piration, palpitation, unconsciousness, and convulsions. 

35. In crowded and badly ventilated apartments, the air is 
breathed over until it contains from six to ten times the natural 
amount of carbonic acid. This contaminated air causes dullness, 
drowsiness, and faintness, because the dark, impure blood circulates 
through the brain, oppressing that organ, and causing it to act like a 
blunted tool. This is a condition not uncommon in our schools, 
churches, and court-rooms — the places of all others where it is desir- 
able that the mind should be alert and free to act ; but, unhappily, 



33. In the open air? Amount of carbonic acid exhaled by a man? A gas-burner* 
room fire ? From furnaces ? 

34. Effects of inhaling carbonic acid alone? In small quantities? 

35. Effects of the air in crowded and badly- ventilated rooms ? 



170 RESPIRATION. 

an unseen physiological cause is at work, dispensing weariness and 
stupor over pupils, audience, and juries. {Read Notes 5 and 6.) 



5. The Ground- Atmosphere and its Relations to Dwellings 

"The soil, which naturally contains wholesome air, and gives facility to its 
every movement, is not less permeable by poisonous gases, which are often 
found to pervade and issue from it. It is easy to find illustrations of the fact 
that people are poisoned through the ground, since it is almost a daily occur- 
rence. Here is one, related by an eminent authority, von Pettenkofer : — ' In 
a residence at Augsburg, apparently endowed with every qualification for health 
and comfort, several priests lived together. On a certain morning, one of 
these, not the least zealous and prompt in the performance of his duties, was 
missed from his usual post at the matin service. His colleagues hurried back 
to their common dwelling in search of the missing priest, and found him lying 
prostrate and insensible upon the floor of his bed-chamber. A doctor was 
immediately called in, and at the first sight of his patient, declared him to be 
suffering from an attack of typhus fever. The Sisters of Charity, upon whom 
devolved the duty of nursing him, and those clerical associates who were 
active in their sympathy and prompt to visit him and give assistance, were, a 
few hours after, attacked in the same way. The doctor did not hesitate in his 
diagnosis, and pronounced the additional cases also typhus fever. A general 
alarm prevailed in the city, and many called at the house of the priest, who 
was greatly beloved. Among others was an old woman, who discovered a 
strong smell of gas, and believing this to be the cause of the sickness, obtained 
permission to remove the priest to her own house. The priest had no sooner 
breathed the fresh air than he began to revive, and during the very first evening 
of his removal to the new abode he became so much better as to make an im- 
portunate demand for food. He soon got entirely well. The old woman, thus 
confirmed in her gas theory, and eager to save the remaining patients, who had 
continued to increase in number in the priests' house, now had an interview 
with the manager of the gas-works which supplied the town, and prevailed 
upon him to investigate the condition of the gas-pipes in the vicinity of the 
priests' residence. This was done, and a leak from which the gas was escaping 
into the ground was found and stopped. The air of the house was perceived 
at once to improve, and with it the health of the patients that were not re- 
moved ; these finally completely recovered from what the doctor even was 
compelled to admit was not typhus fever, but poisoning by gas.' " — Tlie Book 
of Health. 

6. Pure Air and Good Morals. — "Cleanliness and self-respect go to- 
gether, and it is no paradox to affirm that you tend to purify men's thoughts 
and feelings when you purify the air they breathe. * * * * With a low 
average of popular health you will have a low average of national morality, 
and probably also of national intellect. Drunkenness and vice of other kinds 



RESPIRATION. 171 

36. Another unmistakable result of living in and breathing foul 
air is found in certain diseases of the lungs, especially consumption. 
For many years the barracks of the British army were constructed 
without any regard to ventilation ; and during those years the 
statistics showed that consumption was the cause of a very large 
proportion of deaths. At last the government began to improve the 
condition of the buildings, giving larger space and air-supply ; and 
as a consequence, the mortality from consumption has diminished 
more than one-third. 

37. The lower animals confined in the impure atmosphere of 
menageries, contract the same diseases as man. Those brought 
from a tropical climate, and requiring to be closely housed, generally 
die of consumption. In the Zoological Gardens of Paris, this disease 
affected nearly all monkeys, until care was taken to introduce 
fresh air by ventilation, and then it almost wholly disappeared. 
The tendency of certain occupations to shorten life is well known, 
disease being occasioned by the fumes and dust which arise from 
the materials employed, in addition to the bad air of the workshop 
or factory, where many hours are passed daily. {Read Note 7.) 

will flourish in such a soil, and you cannot get healthy brains to grow on un- 
healthy bodies. " — Lord Derby. 

7. Consumption is Lung Starvation. — " The practice of allowing the 
lungs only improper food, in the form of vitiated air, is one of the most preva- 
lent habits of civilized life, and diseases of the lungs are its greatest bane and 
greatest dread. More persons die by consumption than by any other single 
disease. If there be added to those the large number that perish every year by 
inflammation of the lungs and bronchial tubes, disease and premature death 
may be well said to have in these organs their chief citadel. The leading 
cause of all this is, undoubtedly, the poor quality of the food on which the 
lungs are nurtured. The very best physicians, when their attention is 
directed to the subject, admit the full force of this conclusion, and that it has 
not received the attention it deserves. Professor Hartshorne remarks on this 
point, that ' the influence of impure air in promoting consumption has 
probably heretofore been underrated. ' ' The vitiated air of the European bar- 
rack system for soldiers,' says Professor Parkes, * is the only way in which the 
great prevalence of consumption in European armies can be accounted for. ' 
This is the conclusion to which the Sanitary Commissioners for the army came, 



36. A cause of consumption ? How was the fact illustrated ? 

87. How, in the case of the lower animals ? Tendency of certain occupations? 



172 RESPIRATION. 

38. The following table shows the comparative amount of car- 
bonic acid in the air under different conditions, and the effects 

sometimes produced: — 

i 

PROPORTION OP CARBONIC ACID. In 1000 parts of Air 

Air of country 4 

Air of city 5 

In hospital, well ventilated 6 

In school, church, etc. , fairly ventilated 1. 2 to 2. 5 

In court-house, factory, etc., without ventilation. 4. to 40. 

In bed-room, before being aired 4.5 

In bed-room, after being aired 1.5 

Constantly breathed, causing ill health 2. 

Occasionally breathed, causing discomfort 3. 

Occasionally breathed, causing distress 10. 

Expired air 40. 

Air no longer yielding oxygen 100. 






39. Nature's Provision fop Purifying the Air. — We have seen 
that carbonic acid is heavier than air, and is poisonous. Why, then, 
does it not sink upon and overwhelm mankind with a silent, invisi- 

in their celebrated report : ■ A great amount of phthisis (consumption) has 
prevailed in the most varied stations of the army and in the most beautiful 
climates — in Gibraltar, Malta, Ionia, Jamaica, Trinidad, Bermuda, etc. — in all 
of which places the only common condition was the vitiated atmosphere which 
our barrack system everywhere produced. And, as if to clinch the argument, 
there has been of late years a most decided decline in phthisis in these stations, 
while the only circumstance which has notably changed in the time has been 
the condition of the air.' A very eminent authority, the late Dr. Marshall 
Hall, of England, said, in reference to pure air in the treatment of consump- 
tion, ' If I were seriously ill of consumption, I would live out doors day and 
night, except in rainy weather, or midwinter ; then I would sleep in an un- 
plastered log house. Physic has no nutriment, gaspings for air cannot cure 
you, monkey capers in a gymnasium cannot cure you, and stimulants cannot 
cure you. "What consumptives want is pure air, not physic — pure air, not 
medicated air — plenty of meat and bread. ' Let it be remembered, in this con- 
nection, that every hygienic or health-promoting measure which tends to cure 
a disease is much more efficacious in preventing it. " — Black's Ten Lavjs of 
Health. 

38. Give the fact as set forth in the table ? 

39. What can you state of the diffusive power of gases ? The added influence of the 
winds? 



RESPIRATION. 173 

We wave of death ! Among the gases there is a more potent force 
than gravity, which forever prevents such a tragedy. Jt is known 
as the diffusive power of gases. It acts according to a definite law, 
and with a resistless energy compelling these gases, when in contact 
to mingle until they are thoroughly diffused. The added influence 
of the winds is useful, hy insuring more rapid changes in the air, 
ail in motion being perfectly wholesome. The rains also wash 
the air. 

40. We have seen that the whole animal creation is constantly 
taking oxygen from the atmosphere, and as constantly adding to it 
vast volumes of a gas, which is, even in small quantities, injurious 
to both man and animals. How, then, does the air retain, un- 
changed, its life-giving properties ? The uniform purity of the air 
is secured by means of the vegetable creation. Carbonic acid is the 
food of the plant, and oxygen is its waste product. The leaves are 
its lungs, and under the stimulus of sunlight a vegetable respiration 
is set in motion, the effects of which are just the reverse of that of 
animals. Thus nature purifies the air, and at the same time builds 
up beautiful and useful worlds — the life of each growing out of the 
decay of the other. {Read Note 8.) 

8. Plants and the Air. — " Though the air is dependent for the renewal of 
its oxygen on the action of the green leaves of plants, it must not be forgotten 
that it is only in the presence and under the stimulus of light that these organ- 
isms decompose carbonic acid. All plants, irrespective of their kind or nature, 
absorb oxygen and exhale carbonic acid in the dark. The quantity of noxious 
gas thus eliminated is, however, exceedingly small when compared with the 
oxygen thrown out during the day. Aside from the highly deleterious action 
that plants may exert on the atmosphere of a sleeping-room, by increasing the 
proportion of carbonic acid during the night, there is another and more 
important objection to be urged against their presence in such apartments. 
Like animals, they exhale peculiar volatile organic principles, which in many 
instances render the air unfit for the purposes of respiration. Even in the days 
of Andronicus this fact was recognized, for he says, in speaking of Arabia 
Felix, that ' by reason of myrrh, frankincense, and hot spices there growing, 
the air was so obnoxious to their brains, that the very inhabitants at some 
times cannot avoid its influence.' What the influence on the brains of the 
inhabitants may have been does not at present interest us ; we have only 



40. How is the constant purity of the air secured ? Explain the process ? 



174 RESPIRATION. 

41. In the sea, as in the air, the same circle of changes is observed. 
Marine animals consume oxygen and give off carbonic acid, while 
marine plants consume carbonic acid, and liberate oxygen. Taking 
advantage of this fact, we may so arrange aquaria with fishes aad 
sea-plants, in their proper combinations, that each may supply the 
needs of the other, and the water may seldom require to be renewed. 
This affords us, on a small scale, an illustration of the grand circle 
of changes taking place in the air about us, and also of the harmo- 
nious dependence of the two great kingdoms of nature. • 

42. Ventilation. — Since the external atmosphere, as provided by 
nature, is always pure, and since the air in our dwellings and other 
buildings is almost always impure, it becomes imperative that there 
should be a free communication from the one to the other. This we 
aim to accomplish by ventilation. As our houses are ordinarily 
constructed, the theory of ventilation, " to make the internal as pure 
as the external air," is seldom carried out. Doors, windows, and 
flues, the natural means of replenishing the air, are too often closed, 
almost hermetically, against the precious element. Special means, 
or special attention, must therefore be used to secure even a fair 
supply of fresh air. This is still more true of those places of public 
resort, where large numbers of persons are crowded together. (See 
Drainage, Appendix.) 

43. If there are two openings in a room, one as a vent for foul 
air, and the other an inlet for atmospheric air, and if the openings 
be large in proportion to the number of air consumers, the principal 
object will be attained. Thus, a door and window, each opening 
into the outer air, will ordinarily ventilate a small apartment ; or a 
window alone will answer, if it be open both above and below, and 

quoted the statement to show that long ago the emanations from plants were 
regarded as having an influence on the condition of the air ; and, in view 
of our present ignorance, it would be wise to banish them from our sleeping 
apartments, at least until we are better informed regarding their true proper- 
ties. " — Draper on Poisoned Air. 



41. What process occurs in the sea? How is the fact illustrated ? 

42. Character of the external air? Of the air in our dwellings ? What hecomes impera- 
tive ? Imperfect ventilation of our dwellings ? 

43. What hints are given for the ventilation of our dwellings ? 



RESPIRATION. 



175 



the open space at each end be not less than one inch for each occu- 
pant of the room, when the window is about a yard wide. The 
direction of the current is generally from below upward, since the 
foul, heated air tends to rise ; but this is not essential.* Its rate 
need not be rapid ; a " draught," or perceptible current, is never 
necessary to good ventilation. The temperature of the air admitted 
may be warm or cold. It is thought by many that if the air is 
cold, it is pure ; but this is an error, since cold air will receive and 
retain the same impurities as warm air. 

44. Shall we open our bed-rooms to the night air 1 Florence 
Nightingale says, in effect, that night air is the only air we can 
then breathe. " The choice is between pure air without and im- 
pure air within. Most 
people prefer the lat- 
ter — an unaccountable 
choice. An open win- 
dow, most nights in the 
year, can hurt no one. 
In great cities, night air 
is the best and purest to 
be had in twenty-four 
hours. I could better 

* When the window is of 
the common sash kind, a 
good supply of fresh air 
may be obtained without a 
current, by placing a strip 
of board about four inches 
wide under the lower sash 
(Fig. 47). The window is 
thus closed against rain and 
snow, but allows of a supply 
of fresh air to enter between 
the sashes. If still more 
ventilation is needed to keep 
the air of the room sweet, the same arrangement may be made at the top of 
the window. 




Fig. 47.— Showing manner of ventilating by in- 
serting strip of wood beneath lower sash of 
window. 



44. State what Florence Nightingale says about inhaling night air ? 



176 RESPIRATION. 

understand, in towns, shutting the windows during the day than 
during the night." {Read Note 9.) 

45. Animal Heat. — Intimately connected with respiration is the 
production of animal heat, or the power of maintaining the tempera- 
ture of the body above that of the medium in which the creature 
moves ; thus, the bird is warmer than the air, and the fish than 
the water. This elevation of temperature is the result of the va- 
rious chemical changes which are constantly taking place in the 
system. Although common to all animals, in a greater or less de- 
gree, heat is not peculiar to them, since plants also generate it, 
especially at the time of sprouting and flowering. If a thermometer 
be placed hi a cluster of geranium flowers, it will indicate a tem- 
perature several degrees above that of the surrounding air. 

46. Among animals great differences are noticed in this respect, 
but the degree of heat produced is always proportional to the activ- 
ity of respiration and the amount of oxygen consumed. Accord- 
ingly, the birds, whose habits are extremely active, and whose 
breathing capacity is the greatest, have uniformly the highest tem- 
perature. Sluggish animals, on the contrary, as frogs, lizards, and 
snakes, have little need for oxygen, and have incompletely developed 
lungs ; these animals are cold to the touch — that is, they have rela- 
tively a lower temperature than man, and their positive temperature 

9. Pure Air in our Homes during Cold Weather. — "Fresh air 
is the great natural disinfectant, antiseptic, and purifier, and not to be com- 
pared for a moment with any of artificial contrivance. There is plenty of it 
in the world ; yet, disguise the fact as we may, there is no getting over the 
unwelcome truth, that to provide it in abundance in our climate is expensive, 
since during seven months in the year it must be artificially warmed, in order 
that our homes may be comfortable. To take in air at the average winter 
temperature of 28°, raise it to 68°, and discharge it again from our houses even 
once in an hour, is a process which cannot be accomplished without paying 
roundly ; yet on no other condition can we reasonably expect health and long 
life. The best way is to freely admit that it is expensive, but worth the money 
it costs. If Benjamin Franklin thought that ' a penny saved is a penny 
earned,' he is equally sure that 'health is wealth.' " — George Derby on the 
Prevention of Disease. 

45. Warmth of the bird as compared with that of the air? Of the fish and the water? 
Heat in animals and plants? How illustrated with the thermometer? 

46. Amount of heat in animals, how apportioned ? As regards the birds ^ogs, and 
other sluggish animals? Arrangement made by zoologists? 



RESPIRATION. 177 

is but little above that of the external air. Accordingly, zoologists 
have so arranged the animal kingdom that warm-blooded animals, 
including man, the birds, and the quadrupeds, are classified to- 
gether; while the cold-blooded animals, such as the fish, tortoise, 
frog, and all that have no vertebral column, are classed by them- 
selves. 

47. The temperature of the human body is about 100° Fahren- 
heit, and remains about the same through winter and summer — in 
the tropics as well as in the frozen regions of the north. It may 
change temporarily within the range of about twelve degrees ; but 
any considerable, or long-continued elevation or diminution of the 
bodily heat is certain to result disastrously. 

48. Man is able to adapt himself to all extremes of climate; 
and, in fact, by means of clothing, shelter, and food, is able to 
create for himself an artificial climate wherever he chooses to reside. 
The power to resist cold consists chiefly in preventing the heat 
which is generated by the vital processes of the body from being 
lost by radiation. Warm clothing, such as we wear in winter, has, 
in reality, the same temperature as that which is worn in summer ; 
but, by reason of being thick and porous, it is a bad conductor of 
heat, and thus prevents the escape of that produced by the body. 
If woollen fabrics were intrinsically warm, no one would wrap a 
piece of flannel, or blanket, around a block of ice to prevent its 
melting in summer. 

49. The faculty of generating heat explains how it is that we 
are enabled to resist the effects of cold ; but how does the body 
withstand a temperature higher than its ownl Men have been 
known to remain several minutes in an atmosphere heated above 
the boiling-point of water, and yet the temperature of their own 
bodies was not greatly increased. Those who labor in foundries 
and glass-works are habitually subjected to very high degrees of 
temperature, but they do not suffer in health more than those en- 
gaged in many other occupations. 

50. The regulation of the temperature of the body is effected by 

47. State what is said respecting the temperature of the human body. 

48. Ability of man to adapt himself to different climates ? In what does the power to 
resist cold consist ? What is said about warm clothing ? 

49. Men in an atmosphere above the boiling-point ? In foundries and glass-works ? 

50. The regulation of the temperature of the body. Give the «xplanation 



178 RESPIRATION. 

means of perspiration, and by its evaporation. So long as the skin 
acts freely, and the air freely absorbs the moisture, the heat of the 
body does not increase, for whenever evaporation takes place, it is 
attended with the abstraction of heat — that is, the part becomes 
relatively colder. This may be tested by moistening some part of the 
surface with cologne, ether, or other volatile liquid, and then caus- 
ing it to evaporate rapidly by fanning. The principle that evapo- 
ration produces cold has been ingeniously and practically employed, 
in the manufacture of ice by means of freezing machines. {Read 
Note 10. ) 

10. Animal Heat. — "Infants produce much less heat during their early 
days than during any later period of their life ; their temperature falls very 
easily, therefore, and the influence of cold is especially hurtful to them. For 
this reason, and because those who have care of them do not know the facts, 
young children die from exposure in much larger numbers during the winter 
than any other season of the year. * * * * But how is it that warm-blooded 
animals can preserve their own proper heat when they are placed in an air that 
is hotter than their bodies ? A man, for example, can remain for a certain 
time in an oven where the air is raised to a temperature nearly equal to that of 
boiling water, without a marked increase of the heat of the body ; it rises a 
few degrees only. Exposures of this kind cannot be long continued, on 
account, as it is supposed, of an expansion of the blood. A case is on record 
of a person remaining ten minutes in a dry hot-air bath, at 284 degrees, or- 
seventy-two degrees above the boiling-point of water ; and Chabert, the so- 
called Tire King,' went into ovens heated from 400 to 600 degrees, but, of 
course, for a much shorter period. Sun heat is often fatal, even in the tem- 
perate zone, but still more frequently in the tropics, amongst troops on the 
march and amongst coolies working on plantations or on public works. In 
Pekin, during about ten days in July, 1743, the thermometer stood at the 
extreme height of 104 degrees in the shade, and, in that period, 11,400 people 
died. Habit accustoms the Chinese, negroes, and others to bear a greater heat 
than the natives of temperate climates can support. The faculty of resisting 
heat depends upon the evaporation of water, which takes place continually 
from the skin and lungs, and which constitutes the ' cutaneous and pulmonary 
transpiration ; ' for water, as it changes into vapor, carries off the caloric of 
whatever surrounds it, and thus the body is cooled in proportion as the exter- 
nal heat warms it. It is on this principle that water placed in certain porous 
vessels called ' alcarazas, ' becomes cool so promptly, even in midsummer. 
These vases permit the water contained in them to leak out through numerous 
pores, so that their surface is constantly moist ; by a rapid evaporation of this 
moisture, the liquid within is made cool." — Milne-Edwards on " Zoologie." 



RESPIRATION. 179 

51. Spontaneous Combustion. — Is it possible that the tempera- 
ture of the living body can be so increased that its tissues will 
burn spontaneously 1 From time to time, cases have been reported 
in which, by some mysterious means, considerable portions of the 
human body have been consumed, apparently by fire — the victim 
being found dead, or incapable of explaining the occurrence, 
flence, the theory has been current that, under certain conditions, 
the tissues of the body might become self-ignited ; and the fact that 
this so-called spontaneous combustion has ordinarily taken place in 
those who had been addicted to the use of alcoholic drinks, has 
given a color of probability to the opinion. It has been supposed 
that the flesh of these unfortunate persons, becoming saturated with 
the inflammable properties of the alcohol thus taken into the sys- 
tem, took fire upon being exposed to a flame, as of a lighted candle, 
or, indeed, without any external cause. But, whether this be pos- 
sible or not, one thing is certain — this strange kind of combustion 
has never been actually witnessed by any one competent to give a 
satisfactory account of it. 

52. The results that have been observed may be satisfactorily 
explained by the accidental ignition of the clothes, or other articles 
near the body, and by the supposition that the individual was 
at the time too much stupefied by intoxication, to notice the 
source of danger and provide for his safety. The highest tempera- 
ture that has been observed in the body — about 112° Fahrenheit — is 
too low to ignite the vapor of alcohol ; much less will it cause the 
burning of animal tissues. It is undoubtedly true that when the 
tissues are filled with alcohol, combustion will more easily take 
place than when the body is in a normal state ; but, under any con- 
dition, the combustion of the body requires a higher degree of heat 
than can be generated by the body itself, or the mere proximity of 
a lighted candle, or any cause, of similar character. 

51. State what is said of spontaneous combustion. 
62. How is the theory refuted? 



I 



180 RESPIRATION. 



QUESTIONS FOR TOPICAL REVIEW. 

PAG£ 

1. What is the object of respiration ? 154 

2. What are the special organs of respiration ? „ 154 

3. In what organs does a change in the blood take place ? 154 

4. "What is the nature of the change ? 154 

5. "Where are the lungs situated, and what is the character of the substamce of which 

they are composed ? 154 

6. Describe the facilities provided for the lung movements 154, 155 

7. Describe the trachea, or windpipe 155-158 

8. Describe the bronchial tubes, and their uses 155, 156 

9. What can you state in relation to the epiglottis ? 156, 157 

10. What are the cilia and what use do they probably serve ?. 157 

11. How may the lungs be affected by not being properly protected ? 158 

12. Describe the movements necessary to the act of perfect respiration 159 

13. What is the diaphragm, and what is its office ? 159 

14. How may the organs of respiration be so improved as to increase their capacity and 

power? 159 

15. What is stated in relation to the frequency of respiration? 159,160 

16. To what extent may the act of respiration be subjected to our wills ? 160 

17. What may be said to be the capacity of the lungs ? 160 

18. How long does it take every particle of air in the lungs to be expelled and new air to 

take its place ? 160, 161 

19. What would be the consequences, if the entire capacity of the lungs were constantly 

used? 161 

20. What would be the consequences to a fish put into water from which the air had 

been completely exhausted ? Why?. 161 

21. What is the air, and what are its parts? 162, 163 

22. What is the character of the air that has been just breathed ? 162 

23. Why is it that such air is not fit for respiration ? 163, 164 

24. What are the effects, as recorded in notable cases of confinement in places the air of 

which has been breathed " over and over ? " 163 

25. What can you state of changes in the blood from respiration ? 164 

26. What of the air as an article of food ? 164 

27. What on the subject of interchange of gases in the lungs ? 164, 165 

28. Explain the difference between arterial and venous blood 165 

29. Explain, if you can, the cause of the difference 165 

30. State what you can in relation to blue blood 165 

31. In relation to the amount of labor exerted in respiration 166 

32. In relation to the deleterious properties of different gases 166, 167 

33. In relation to the dust that floats in the air 168 

34. What are the properties of carbonic acid gas ? 168, 169 

35. In what places is carbonic acid gas commonly found ? 169 

36. Describe the effects of carbonic acid gas ■ 169 

3T. What are the general effects of breathing any impure atmosphere ? 169-172 

38. What are Nature's provisions for purifying the air? 172,173 

39. What hints and directions are given on the subject of ventilation ?. 174, 175 

40. How does the temperature of the body compare with the medium in which it lives? 176 

41. How is temperature of the body regulated and sustained ? 177, 178 

42. State what you can on the subject of spontaneous combustion 179 




CHAPTER IX. 

J The Nervous System. 




inimal and Vegetative Functions Sensation, Motion, and Volition — The 
Structure of the Nervous System — The White and Gray Substances — The 
Brain — Its Convolutions — The Cerebellum — The Spinal Cord and its 
System of Nerves — The Anterior and Posterior Roots — The Sympathetic 
System of Nerves — The Properties of Nervous Tissue — Excitability of Nerv- 
ous Tissues — The Functions of the Spinal Nerves and Cord — The Direction 
of the Fibres of the Cord — Reflex Activity, and its Uses — The Functions of 
the Medulla Oblongata and the Cranial Ganglia — The Reflex Action of the 
Brain — Effects of Alcohol, Tobacco, Snuff, Narcotics, Opium, Chloral, 
Hasheesh, Chloroform. 

1. Animal Functions. — The vital processes which we have been 
considering in the three previous chapters — of digestion, circulation, 
and respiration — belong to the class of functions known as vegeta- 
tive functions. That is, they are common to vegetables as well as 
animals ; for the plant, like the animal, can originate nothing, not 
even the smallest particle of matter ; and yet it grows, blossoms, 
and bears fruit, by reason of obtaining and digesting the nutriment 
which the air and soil provide. The plant has its. circulatory fluid 
and channels, by which the nutriment is distributed to all its parts. 
It has, also, a curious apparatus in its foliage, by which it abstracts 
from the air those gaseous elements so necessary to its support ; and 
thus it accomplishes vegetable respiration. These vegetative func- 
tions have their beginning and end within the organism of the 
plant; and their object is the preservation of the plant itself, as 
well as of the entire species. 

2. The animal, in addition to these vegetative functions, has an- 
other set of powers, by the use of which he becomes conscious of a 
world external to himself, and brings himself into active relations 



1. What processes are known as the vegetative functions? Why so called ? What prop- 
erties and functions does the plant possess ? Their object ? 

2. What second set of powers has the animal ? What functions are mentioned ? The ad- 
vantage they give? 



182 THE NERVOUS SYSTEM. 

with it. By means of the vegetative processes, his life and species 
are maintained ; while, by means of certain animal functions, he 
feels, acts, and thinks. These functions, among which are sensa- 
tion, motion, and volition, not only distinguish the animal from the 
plant, but, in proportion to their development, elevate one creature 
above another ; and it is by virtue of his pre-eminent endowment, 
in these respects, that man holds his position at the head of the 
animal creation. 

3. Among animals whose structure is very simple — the hydra, or 
fresh-water polyp, being an example — no special organs are em- 
powered to perform separate functions, but every part is endowed 
alike ; so that, if the animal be cut into pieces, each portion has all 
the properties of the entire original ; and, if the circumstances be 
favorable, each of the pieces will soon become a complete hydra. 
As we approach man, in the scale of beings, we find that the 
organs multiply, and the functions become more complete. The 
function of motion, the instruments of which — the muscles and 
bones — have been considered in former chapters, and all the other 
animal functions of man, depend upon the set of organs known as 
the nervous system. 

4. The Nervous System. — The intimate structure of this sys~ 
tern differs from any tissue which we have before examined. It is 
composed of a soft, pulpy substance, which early in life is almost 
fluid, but which gradually hardens with the growth of the body. 
When examined under the microscope, it is found to be composed 
of two distinct elements : (1) the white substance, composing the 
larger proportion of the nervous organs of the body, which is formed 
of delicate cylindrical filaments, about -goVo °^ an mc ^ m diameter, 
termed the nerve-fibres ; and (2) the gray substance, composed of 
grayish-red, or ashen-colored cells, of various sizes, generally possess- 
ing one or more off-shoots, which are continuous with the nerve- 
fibres just mentioned. 

5. The gray, cellular substance constitutes the larger portion of 

3. Animals whose structure is simple? As we approach man? Dependence of the 
animal functions of man ? 

4. The nervous tissues, of what composed ? When examined by the aid of the microscope? 
The white substance ? The gray substance ? 

5. Nervous centres and ganglia? Nerves? What do they serve? Cerebro-spinal 
system 1 



THE NERVOUS SYSTEM. 183 

those important masses which, hear the name of nervous centres and 
ganglia (from ganglion, a knot), in which all the nerve-fibres unite. 
These white nerve-fibres are found combined together in long and 
dense cords, called nerves (from neuron, a cord), which serve to 
connect the nervous centres with each other, and to place them in 
communication with all the other parts of the body which have 
sensibility or power of motion. That part of the nervous system 
which is concerned in the animal functions comprises the brain, the 
spinal cord, and the nerves which are derived therefrom ; these are, 
together, called the cerebrospinal system (Fig. 48) ; while that 
other set of organs, which presides over and regulates the vege- 
tative functions, is called the sympathetic system of nerves. 

6. The Brain. — The brain is the great volume of nervous tissue 
that is lodged within the skull. It is the largest and most complex 
of the nervous centres ; its weight, in the adult, being about fifty 
ounces, or one-fortieth of that of the whole body. The shape of the 
brain is oval, or egg-shaped, with one extremity larger than the 
other, which is placed posteriorly in the skull, to the concavity of 
which it very closely conforms. The brain consists chiefly of two 
parts ; the cerebrum, or brain proper,, and the cerebellum, or " little 
brain." In addition to these, there are several smaller organs at the 
base, among which is the commencement or expansion of the spinal 
cord, termed the medulla oblongata., or oblong marrow. 

7. The tissue of the brain is soft and easily altered in shape by 
pressure ; it therefore requires to be placed in a well-protected position, 
such as is afforded by the skull, or cranium, which is strong with- 
out being cumbrous. In the course of an ordinary lifetime, this bony 
box sustains many blows with little inconvenience ; while, if they 
fell directly upon the brain, they would at once, and completely, 
disorganize that structure. Within the skull, the brain is enveloped 
by certain membranes, which at once protect it from friction and 
furnish it with a supply of nutrient vessels ; they are called the 
arachnoid, or " spider's web," the dura mater, and the pia mater, or 
the "tough" and "delicate coverings." The supply of blood sent 

6. Location of the brain ? Its weight? Its shape? Of what it consists? What organs 
at the base? 

7. The tissue of the brain ? What, therefore, is required? Blows on the head? Mem- 
branes of the brain ? Blood sent to the br^in ? 



184 



THE NERVOUS SYSTEM. 




Fig. 48.— The Cerebrospinal System. 



THE NERVOUS SYSTEM. 



185 



to the brain is very liberal, amounting to one-fifth of all that, the 
entire body possesses. The brain of man is heavier than that of 
any other animal, except the elephant and whale. 

8. The Cerebrum. — The brain proper, or cerebrum, is the 
largest of the intracranial organs, and occupies the entire upper and 
front portion of the skull. It is almost completely bisected by a 
fissure, or cleft, running through it lengthwise, into two equal parts 
called hemispheres. The exterior of these hemispheres is gray in 
color, consisting chiefly of nerve-cells, arranged so as to form a layer 
of gray matter one-fifth of an inch in thickness, and is abundantly 
supplied with blood-vessels. The interior of the brain, however, is 
composed almost wholly of white substance, or nerve-fibres. 

9. The surface of the 
cerebrum is divided by a 
considerable number of 
winding and irregular fur- 
rows, about an inch deep, 
into " convolutions," as 
shown in Fig. 49. Into 
these furrows the gray 
matter of the surface is 
extended, and, in this 
manner, its quantity is 
vastly increased. The ex- 
tent of the entire surface 
of the brain, with the 
convolutions unfolded, is 
computed to be equal to 
four square feet ; and yet 
it is easily enclosed within 
the narrow limits of the 
skull. When it is stated 
that the gray matter is 
the true source of nervous power, it becomes evident that this 




-Upper Surface of the Cerebrum. 

A, Longitudinal Fissure. 

B, The Hemispheres. 



8. Size of the brain proper? How divided? The exterior of the hemispheres? The in- 
ferior? 

9. The surface of the cerebrum, how marked? The gray matter of the surface? Extent 
t>f the entire brain surface ? Source of nervous power ? What further ? 



186 



THE NERVOUS SYSTEM. 



arrangement has an important bearing on the mental capacity of 
the individual. And it is noticed that in children, before the mind 
is brought into vigorous use, these markings or furrows on the sur- 
face are comparatively shallow and indistinct ; the same fact is true 
of the brain in the less civilized races of mankind and in the lower 
animals. It is also noticeable that among animals, those are the 
most capable of being educated which have the best development of 
the cerebrum. {Read A T ote 1.) 




Fig. 50.— Vertical Section of the Brain 
A, Left Hemisphere of Cerebrum. D, The Pons Varolii 



B, Corpus Callosum. 

C, Optic Thalamus. 



E, Upper extremity of the Spinal Cord. 

F, The Arbor Vitte. 



1, The Brain. — "Our brains are seventy-year clocks. The Angel of Life 
winds them up once for all, then closes the case, and gives the key to the 
Angel of the Resurrection. Tic-tac ! tic-tac ! go the wheels of thought ; our 
will cannot stop them ; they cannot stop themselves ; sleep cannot stop them ; 
madness only makes them go faster ; death alone can break into the case, and, 
seizing the ever-swinging pendulum, which we call the heart, silence at last 
the clicking of the terrible escapement we have carried so long beneath our 
wrinkled foreheads. * * * Xow, when a gentleman's brain is ill-regulated 
or empty, it is, to a great extent, his own fault, and so it is simple retribution 
that, while he lies slothfully or aimlessly dreaming, the fatal habit settles on 
him like a vampire and sucks his blood, fanning him all the while with its hot 
wings into deeper slumber or idler dreams." — Holmes' The Autocrat of the 
Freakfast- Table, 



THE NERVOUS SYSTEM. 187 

j\IO. The Cerebellum. — The " little brain" is placed beneath the 
'posterior part of the cerebrum, and, like the latter, is divided into 
hemispheres. Like it, also, the surface of the cerebellum is com- 
posed of gray matter, and its interior is chiefly white matter. It 
has, however, no convolutions, but is subdivided by many parallel 
ridges, which, sending down gray matter deeply into the white, 
central portion, give the latter a somewhat branched appearance. 
This peculiar appearance has been called the arbor vitce, or the 
"tree of life," from the fact that when a section of the organ is 
made, it bears some resemblance to the trunk and branches of a 
tree (Fig. 50, F). In size, this cerebellum, or " little brain," is less 
than one-eighth of the cerebrum. 




Fig. 51.— Lower Surface of the Brain. 
The numbers refer to the pairs of nerves. 



II. From the under surface of the cerebrum, and from the front 
margin of the cerebellum, fibres collect together to form the medulla 
oblongata (Fig. 51, Ma), which, on issuing from the skull, enters 
the spinal column, and then becomes known as the spinal cord. 



10. Location of the " little brain ?" How divided ? Its surface and interior? Its sub 
divisions ? Its size ? 

11. Medulla oblongata? Cranial nerves ? Their shape and position ? 



188 



THE NERVOUS SYSTEM. 



-flip 



From the base of the brain, and from the sides of the medulla 
originate, also, the cranial nerves, of which there are twelve pairs. 

These nerves are round cords of glisten- 
ing white appearance, and, like the 
arteries, generally lie remote from the 
surface of the body, and are well pro- 
tected from injury. 

12. The Spinal Cord— The spinal 
cord, or " marrow," is a cylindrical mass 
of soft nervous tissue, which occupies a 
chamber, or tunnel, fashioned for it in 
the spinal column (Figs. 52 and 53). 
It is composed of the same substances 
as the brain; but the arrangement is ex- 
actly reversed — the white matter encom- 
passing or surrounding the gray matter, 
instead of being encompassed by it. 
The amount of the white substance is 
also greatly in excess of the other mate- 
rial. A vertical fissure partly separates 
the cord into two lateral halves, and 
each half is composed of two separate 
bundles of fibres, which are named the 
anterior and posterior columns. 

13. These columns have entirely dif- 
ferent uses, and each of them unites with 
a different portion of the nerves which 
have their origin in the spinal cord. 
The importance of this part of the 
nervous system is apparent from the 
extreme care taken to protect it from 
external injury. For, while a very slight 
disturbance of its structure suffices to 
disarm it of its power, yet so staunch 
is its bony enclosure, that only by very 



Fig. 52. 



A, Cerebrum, B, Cerebellum, 
D, D, Spinal Cord. 



12. The spinal cord ? Of what composed ? How divided ? Each half? 

13. Uses of these columns? Importance of this part of the nervous system ? How pro 
tected? 



THE NEEVOtJS SYSTEM. 



189 



severe injuries is it put in peril. The three membranes that cover 
the brain are continued downward, so as to envelope and still fur- 
ther shield this delicate organism. 

14. The Spinal Nerves. — The spinal nerves, thirty-one pairs in 
number, spring from each side of the cord by two roots, an anterior 
and a posterior root, which have the same functions as the columns 
bearing similar names. The posterior root is distinguished by pos- 
sessing a ganglion of gray matter, and by a somewhat larger size. 




Fig. 53.— Section of Spinal Cord, with Roots of Spinal Nerves. Front View. 

The successive points of departure, or the off-shooting of these 
nerves, occur at short and nearly regular intervals along the course 
of the spinal cord. Soon after leaving these points, the anterior 
and posterior roots unite to form the trunk of a nerve, which is 
distributed, by means of branches, to the various organs of that 
part of the body which this nerve is designed to serve. The spinal 
nerves supply chiefly the muscles of the trunk and limbs and the 
external surface of the body. 

15, The tissue composing the nerves is entirely of the white 
variety, or, in other words, the nerve-fibres; the same as we have 
observed forming a part of the brain. But the nerves, instead of 
being soft and pulpy, as in the case of the brain, are dense in 
structure, being hardened and strengthened by means of a fibrous 
tissue which surrounds each of these delicate fibres, and binds them 
together in glistening, silvery bundles. Delicate and minutely fine 
as are these nerve-fibres, it is probable that each of them pursues 
an unbroken, isolated course, from its origin, in the brain or else- 

14. The spinal nerves? The posterior root ? The nerves, how arranged ? Their office* 

15. The nerve tissue? Its character ? Course of each nerve fibre? 




190 THE NERVOUS SYSTEM. 

where, to that particu'ar point which it is intended to serve. For. 
although their extremities are often only a hair's breadth distant 
from each other, the impression which any one of them communi- 
cates is perfectly distinct, and is referred to the exact point whence 
it came. 

16. This may be illustrated in a simple manner, thus: if two 
fingers be pressed closely together, and the point of a pin be carried 
lightly across from one to the other, the eyes may be closed, and 
yet we can easily note the precise instant when the pin passes from 
one finger to the other. If the nerve-fibres were less independent, 
and if it were necessary that they should blend with and support 
each other, all accuracy of perception would be lost, and all infor- 
mation thus afforded would be pointless and confused. These 
silvery threads must, therefore, be spun out with an infinite degree 
of nicety. Imagine, for instance, the fibre which connects the brain 
with some point on the foot — its length cannot be less than one 
hundred thousand times greater than its diameter, and yet it per- 
forms its work with as much precision as fibres that are compara- 
tively much stronger, and less exposed. {Read Note 2.) 

17. The Sympathetic System. — The sympathetic system of 
ves remains to be described. It consists of a double chain 

2. How Bodily Sensations are Located. — "A nervous fibre which 
ends in the skin forms, as far as its union with the brain or cord is concerned, 
one long, fine, unbroken thread. The fibres, thus ending in the skin, very 
soon join to form small branches, and finally in thick nerve trunks, but in no 
case do two nerve fibres coalesce so as to lose their identit}^. Every part of 
the skin has its own separate connections with the centre of the nervous 
system, which unite there just as telegraph wires unite at a terminus. The 
brain is the terminus of these lines of nerves, and, as it were, receives and ex- 
plains the messages sent to it. It distinguishes very clearly by what particular 
fibre such a message has come, and just as the clerk in a telegraph office, 
where a great many wires meet from all sides, knows by experience from what 
direction each wire brings its message, so the brain also knows by experience 
what part of the skin is involved when a sensation reaches it along a certain 
nerve fibre. It is probable that the brain, by its imaginative faculty, 
has formed a complete picture of the surface of the body — a kind of chart 

16. How may we illustrate the fact ? The fibre connecting the brain with a point in the 
foot? 

17. The sympathetic system of nerves ? Of what does it consist ? 



THE NERVOUS SYSTEM. 191 

of ganglia, situated on each side of the spinal column, and extend- 
ing through the cavities of the trunk, and along the neck into the 
head. These ganglia are made up for the most part of small col- 
lections of gray nerve-cells, and are the nerve-centres of this 
system. From these, numerous small nerves are derived, which 
connect the ganglia together, send out branches to the cranial and 
spinal nerves, and form networks in the vicinity of the stomach 
and other large organs. A considerable portion of them also 
follows the distribution of the large and small blood-vessels, in 
which the muscular tunic appears. Branches also ascend into the 
head, and supply the muscles of the eye and ear, and other organs 
of sense. 

18. In this manner the various regions of the body are associ- 
ated with each other by a nervous apparatus, which is only 
indirectly connected with the brain and spinal cord, and thus 
it is arranged that the most widely separated organs of the body 
are brought into close and active sympathy with each other, so that 
"if one member suffers, all the other members suffer with it." 
From this fact, the name sympathetic system, or the great sympa- 
thetic nerve, has been given to the complicated apparatus we have 
briefly described. Blushing and pallor are caused by mental 
emotions, as modesty and fear, which produce opposite conditions 
of the capillaries of the face by means of these sympathetic nerves. 
{Read Note 3. ) 

slowly made, and always being more highly perfected, by means of which, with 
each impression from without, there arises in the brain a picture of the spot 
upon the skin where the irritation has taken place. Now, if an irritation 
were to pass from one nerve fibre to another, it is very plain, the brain could 
not tell the place from which it came, and could not localize impressions 
received from the world about us." — Ber lutein's Five Senses of Man. 

3. The Wonderful Operations of the Sympathetic System. — 
Blushing or "Shame-redness."— "A blow upon the head will knock a 
man senseless, but he still lives and survives ; a blow of like violence upon the 
pit of the stomach is followed by instant death, because the great centre of the 
organic nerves lies there, and the vital actions are suspended by the blow, so 
that the system never lives to recover, but abolition of function and of life at 
once follows. Other actions also belong to this organic nervous system. It 



18. Association of the various regions of the body? If one member suffers ? Blushing? 



192 THE NERVOUS SYSTEM. 

19. The Properties of Nervous Tissue. — We have seen that 
in all parts of this system there are only two forms of nervous 
tissue, namely, the gray substance and the white substance, so 
called from their difference of color as seen by the naked eye ; or 
the nerve-cell, and the nerve-fibre, so called from their microscopic 
appearance. Now these two tissues are not commonly mingled 
together, but either form separate organs or distinct parts of the 
same organs. This leads us to the conclusion that their respective 
uses are distinct. And this proves to be the simple fact ; wherever 
we find the gray substance, we must look upon it as perform- 
ing an active part in the system — that is, it originates nervous 
impulses ; the white matter, on the contrary, is a passive agent, and 
serves merely as a conductor of nervous influences. Accordingly, 
the nervous centres, composed so largely of the gray cells, are the 
great centres of power, and the white fibres are simply the instru- 
ments by which the former communicate with the near and distant 
regions of the body under their control. 

20. We may compare the brain, then, to the capital, or seat of 
government, while the various ganglia, including the gray matter of 
the cord, like so many subordinate official posts, are invested with 
authority over the outlying provinces ; and the nerves, with the 

controls the calibre of the blood-vessels, for which end filaments run along 
each of them. The body temperature is maintained by the production and 
dispersion of heat thus regulated, a continuous oscillation going on betwixt 
the internal vessels and those of the skin. It is connected with the emotions ; 
and so the heart beats perceptibly with excitement, and the maiden's cheek 
blushes before words that should never be spoken, or thoughts that should 
never arise. The momentary dilatation of the vessels of the skin constitutes 
the blush (in the German, 'shame-redness'), which is not confined to the face, 
though, of course, it is only seen there — the body being hid by the clothes. " — 
Fothergtll on the Maintenance of Health. 

"There is an old tradition that when the executioner of Charlotte Corday 
lifted her severed head high in air, and smote the face with his hand, the 
cheeks were seen to resent the insult with a blush. This reddening is not 
impossible, for a decapitated head certainly may exhibit, for a time, certain 
reflex movements. But whether sensibility is retained cannot be known." 



19. Properties of nervous tissue? Office of the gray substance ? Of the white? The 
nervous centres ? White fibres ? 

20. What comparison is made between the brain and the nation's capital ? The vital 
property, excitability ? What example is given ? 



THE NERVOUS SISTERI 193 

white matter of the cord, are the highways over which messages go 
and return between these provinces and the local or central govern- 
ments. But both forms of nervous tissue possess the same vital 
property called excitability, by which, term is meant that, when a 
nerve-cell or fibre is stimulated by some external agent, it is capa- 
ble of receiving an impression, and of being by it excited into 
activity. A ray of light, for example, falling upon one extremity 
of a fibre in the eye, excites it throughout its whole length ; and its 
other extremity within the brain, communicating with a nerve-cell, 
the latter in its turn is excited, and the sensation of sight is pro- 
duced. (Read Note 4.) 

21. What sort of change takes place in the nervous tissue when 
its excitability is aroused, is not known ; certainly none is visible. 
On this account, it has been thought by some that the nerve-fibre 
acts after the manner of a telegraph-wire ; that is, it transmits its 
messages without undergoing any material change of form. But 
though the comparison is a convenient one, it is far from being 
strictly applicable, and the notion that nerve-force is identical with 
electricity has been fully proved to be incorrect. 

4. The Relations of the Brain and Sympathetic Nerve. — "Buried 
in the hidden recesses of the body, between the spinal column and the great 
organs of nutrition, there is a double row of small knots of nervous sub- 
stance, bound together by a series of nerves running from one to another, 
in succession, from the neck to the base of the column. The whole 
appears like a long, fine cord, with knots at various distances — a collec- 
tion of little brains, if I may use a rather crude expression. It is, as the 
Swiss would say, the 'great council' of this federative republic, which counter- 
poises that cerebral royalty within us. It has been well named the great 
sympathetic nerve, and this it is which makes the laws by which our 
interior life is governed. The nutritive apparatus of a country, its com- 
merce, its industry, the incessant labor of its citizens, by which the 
public wealth is built up — and also let us add, the throbs of the national 
heart — all this the sympathetic system full plainly shows us should be left to 
itself. It would be a fine affair if the brain had to watch over the service of 
the stomach, or if, at its convenience, it regulated the movements of the 
master who disposes of its life. Besides, what would become of the poor body, 
if the least drowsiness attacked the universal centre ? Happy is it for us — and 
let us not be slow to own it — that nature has armed herself against these en- 
croachments of power."— Mace's The Little Kingdom. 

21. Change in the nervous tissues ? Nerve force and electricity? 

9 



194 THE NERVOUS SYSTEM. 

22. The Functions of the Nerves— The nerves are the in- 
\ N struments of the two grand functions of the nervous system — Sensa- 

\ tion and Motion. They are not the true centres of either function, 
but they are the conductors of influences which occasion both. If 
the nerve in a limb of a living animal be laid bare, and irritated by 
pinching, galvanizing, or the like, two results follow, namely: the 
animal experiences a sensation, that of pain, in the part in which 
the nerve is distributed, and the limb is thrown into convulsive 
action. When a nerve in a human body is cut by accident, or 
destroyed by disease, the part in which it ramifies loses both sensa- 
tion and power of motion; or, in other words, it is paralyzed. We 
accordingly say that the nerves have a two-fold use — a sensory and 
a motor function. 

23. If a nerve that has been exposed be divided, and the inner 
end, or that still in connection with the nerve-centres be irritated, 
sensation is produced, but no movement takes place. But if the 
outer end, or that still connected with the limb, be irritated, then 
no pain is felt, but muscular contractions are produced. Thus we 
prove that there are two distinct sets of fibres in the nerves — one 
of which, the sensory fibres, conduct toward the brain, and another, 
the motor fibres, conduct to the muscles. The former may be said 
to begin in the skin and other organs and end in the brain, while 
the latter begin in the nervous centres and end in the muscles. 
They are like a double line of telegraph wires, one for inquiries, 
the other for responses. 

\24. We have already spoken of the two roots of the spinal 
nerves, called, from their points of origin in the spinal cord, the 
anterior and posterior roots. These have been separately cut and 
irritated in the living animal, and it has been found that the pos- 
terior root contains only sensory fibres, and the anterior root has only 
motor fibres. So that the nerves of a limb may be injured in such 
a way that it will retain power of motion and yet lose sensation ; or 
the reverse condition, feeling without motion, may exist. Between 

22. Functions of the nerves? In the case of the nerve of a living animal? Of the 
human body ? 

23. If an exposed nerve be divided ? What is proved? The course of the sensory set 
of fibres ? Of the motor set ? To what are they likened ? 

24. The two roots of the spinal nerves? What has been found? Difference of the two 
sorts of fibres ? Result of their union ? 



THE NERVOUS SYSTEM. 195 

these two sorts of fibres no difference of structure can be found ; 
and where they have joined to form a nerve, it is impossible to dis- 
tinguish one sort from the other. 

25. Occasionally a nerve is so compressed as to be temporarily 
unable to perform its functions : a transient paralysis then takes 
place. This is the case when the leg or arm " gets asleep," as it is 
expressed. When such is the condition with the leg, and the per- 
son suddenly attempts to walk, he is liable to fall, inasmuch as the 
motor fibres cannot convey orders to the muscles of the limb. An- 
other fact is observed : there is no sensation in this nerve at the 
point of its compression ; but the whole limb is numb, and tingling 
sensations are felt in the foot — the point from which the sensory 
fibres arise. 

26. This illustrates the manner in which the brain interprets all 
injuries of the trunk of a nerve. Sensation or pain is not felt at 
the point of injury, but is referred to the outer extremities of the 
nerve, where impressions are habitually received. This is the rea- 
son why, after a limb has been amputated by the surgeon, the pa- 
tient appears to suffer pain in the member that has been severed 
from the body ; while some form of irritation at the end of the 
nerve in the wound, or stump, is the real source of his distress. 
Again, when the " funny-bone " — that is, the ulnar nerve at the 
elbow — is accidentally struck, the tingling sensations thus produced 
are referred to the outer side of the hand and the little finger, the 
parts to which that nerve is distributed. 

27. All the spinal nerves, and two from the brain, are concerned 
in both sensation and motion. Of the remainder of the cranial 
nerves, some are exclusively motor, others exclusively sensory ; and 
still others convey, not ordinary sensations, but special impressions, 
such as sight, hearing, and smell, which we have yet to consider. 
However much the functions of the nerves seem to vary, there is 
but little difference discoverable in the nerves themselves, when 
examined under the microscope. Whatever difference exists must 

25. Transient paralysis ? When such is the case with the leg ? What other fact is ob- 
served ? 

26. What does this illustrate ? Sensation ? The feeling after a limb has been amputated ? 
Striking of the " funny-bone ? " 

27. The spinal nerves, and two from the brain? Of the remainder? Difference in the 
nerves? How accounted for? The rate of conduction along a nerve? As compared with 
«lectricity ? 






196 THE NERVOUS SYSTEM. 

be accounted for in consequence of the nerves communicating with 
different portions of the gray matter of the brain. The rate of mo- 
tion of a message, to or from the brain along a nerve, has been 
measured by experiment upon the lower animals, and estimated in 
the case of man at about two hundred feet per second. As com- 
pared with that of electricity, this is a very slow rate, but, in respect 
to the size of the human body, it is practically instantaneous. (Read 
Note 5.) 

28. The Functions of the Spinal Cord. — As the anterior and 
posterior roots of the spinal nerves have separate functions, so the 
anterior and posterior columns of the cord are distinct in function. 
The former are concerned in the production of motion, the latter in 
sensation. If the cord be divided, as before in the case of the 
nerve, it is found that the parts below the point of injury are de- 
prived of sensation and of the power of voluntary motion on both 
sides of the body — a form of paralysis which is called paraplegia. 

29. This form of disease — paraplegia — is sometimes seen among 
men, generally as the result of a fall, or some other severe accident, 
by which the bones of the spine are broken, and the cord is crushed, 
or pierced by fragments of bone. The parts which are supplied by 
nerves from the cord above the point of injury are as sensitive 
and mobile as before. The results are similar, whether the division 
happens at a higher or lower portion of the spinal cord ; but the 
danger to life increases proportionally as the injury approaches 
the brain. "When it occurs in the neck, the muscles of inspiration 
are paralyzed, since they are supplied by nerves issuing from that 

5. The Speed of Sensation and Thought. — " The rate of nervous and 
mental action is not the same in all individuals. In comparing the records 
made by astronomers, it has been found that an appreciable difference exists 
in the rapidity with which the same occurrence may be noted by different ob- 
servers. This is known as the 'personal equation,' and is allowed for with the 
greatest nicety in the making up of astronomical reports. With very delicate 
apparatus for marking time, the various nervous impulses have been observed ; 
from forty to a hundred feet in a second are the estimates of different experi- 
ments as to the speed of sensation ; or, as it has been expressed, it would take 
a full-grown whale a second to feel the stroke of a harpoon in his tail. " 

28. Functions of the anterior and posterior columns of the cord? If the cord be divided? 

29. Paraplegia ? Result and danger to life ? When the injury occurs in the neck ? 



THE NERVOUS SYSTEM. 197 

region ; and as a result of this paralysis, the lungs are unable to 
act, and life is speedily brought to a close. 

30. When the spinal cord of an animal has been cut, in experi- 
ment, it may be irritated in a manner similar to that alluded to 
when considering the nerves. If, then, the upper cut surface be 
excited, it is found that pain, referable to the parts below the cut, 
is produced ; but when the lower cut surface is irritated, no feeling 
is manifested. So we conclude that in respect to sensation, the 
spinal cord is not its true centre, but that it is merely a conductor, 
and is therefore the great sensory nerve of the body. When the 
lower surface of the cut is irritated, the muscles of the parts below 
the section are violently contracted. Hence we conclude that, in 
respect to the movements ordered by the will, the spinal cord is not 
their source, but that it acts only as a conductor, and is, accord- 
ingly, the great motor nerve of the body. 

31. Direction of the Fibres of the Cord. — If one lateral half 
of the spinal cord be cut, or injured, a very singular fact is observed. 
All voluntary power over the muscles of the corresponding half of 
the body is lost, but the sensibility of that side remains undimin- 
ished. This result shows that the motor fibres of the cord pursue 
a direct course, while its sensory fibres are bent from their course. 
And this has been proved to be the fact ; for immediately after the 
posterior roots — the conductors of sensory impressions — join the 
posterior columns, they enter the gray matter of the cord, and pass- 
ing over, ascend to the brain on the opposite side. Accordingly, 
the sensory fibres from the right and left sides interlace each other 
in the gray matter ; this arrangement has been termed the decussa- 
tion, or crossing of these fibres. This condition serves to explain 
how a disease or injury of the cord may cause a paralysis of motion 
in one leg, and a loss of sensation in the other. 

32. The direction of the anterior, or motor columns of the cord, 
is downward from the brain. In the cord itself, the course of the 
motor fibres is for the most part a direct one ; but in the medulla 
oblongata, or upper extremity of the cord, and therefore early in 

30. Experiment of cutting the spinal cord of an animal? What inference is drawn? 

31. What singular fact is noticed? What does the result show? 

32. Direction of the anterior or motor columns ? In the cord itself? In the medulla 
oblongata ? The decussation ? 



198 THE NERVOUS SYSTEM. 

their career, these fibres cross from side to side in a mass, and not 
separately, as in the case of the posterior fibres just mentioned. 
This arrangement is termed the decussation of the anterior columns 
of the medulla. 

33. From this double interlacing of fibres results a cross action 
between the original and terminal extremity of all nerve-fibres 
which pass through the medulla — namely, those of all the spinal 
nerves. Consequently, if the right hand be hurt, the left side of 
the brain feels the pain ; and if the left foot move, it is the right 
hemisphere which dictates its movement. For the same reason, 
when a loss of sensation and power of motion affecting the right 
side of the body alone is observed, the physiologist understands that 
the brain has been invaded by disease upon its left side. This 
affection is termed hemiplegia, or the "half -stroke." The full-stroke, 
which often follows the rupture of a blood-vessel in the brain, is 

\ commonly called paralysis. 

34. The Reflex Action of the Cord. — We have already con- 
\ sidered the cord as the great motor and sensory nerve of the body, 

but it has another and extremely important use. By virtue of the 
gray matter, which occupies its central portion, it plays the part of 
an independent nerve centre. The spinal cord not only conducts 
some impressions to the brain, but it also arrests others ; and, as it 
is expressed, " reflects " them into movements by its own power. 
This mode of nervous activity is denominated the reflex action of 
the cord. 

35. A familiar example of this power of the cord is found in the 
violent movements which agitate a fowl after its head has been cut 
off. The cold-blooded animals also exhibit reflex movements in an 
astonishing degree. A decapitated centipede will run rapidly for- 
ward, and will seemingly strive to overturn, or else climb over 
obstacles placed in its way. A frog similarly mutilated will sustain 
its headless body upon its feet, in the standing posture, just as it 
might do if it were still alive. If pushed over, it will regain its 
feet ; and if the feet are irritated, it will jump forward. There can 

33. Result of the double interlacing of fibres? Where is the seat of pain when the right 
hand is hurt ? The moving of the foot? Loss of sensation in one side of the body ? 

34. What other important use has the cord ? What is the activity denominated ? 
35 Example of the fowl ? Ceutipede? Frog? What do they prove? 



THE NERVOUS SYSTEM. 199 

be no doubt that, in the lower animals, movements may take place 
which are completely divorced from the will, sensation, and con- 
sciousness; for in those animals, as well as in man, these faculties 
have their principal seat within the brain. 

36. An irritation is necessary, in most instances, to awaken re- 
flex movements. In the case of the decapitated fowl, its muscles 
are excited to convulsive action by reason of its being thrown upon 
the hard ground and roughly handled. Let it be treated differently, 
and the convulsions will not take place : let it be laid gently upon 
soft cotton, and the body will remain comparatively quiet. It may 
comfort some people to know that the convulsions which follow 
decapitation are not attended with pain, nor are they a necessary 
part of the " act of death," as some suppose. 

37. In the human body, likewise, actions are excited that are 
entirely distinct from the ordinary voluntary efforts. It is not per- 
missible, desirable, nor even necessary to decapitate a man that the 
body may be disconnected from his brain, in order to test the effect 
of irritation upon the spinal cord — although the bodies of beheaded 
criminals have been experimented upon, and caused to move by 
powerful galvanic batteries. Such experiments are rendered un- 
necessary by the occurrence of certain deplorable cases of disease 
and injury, which effectually sever all communication between the 
brain and a large part of the body. 

38. Thus, the cord by an accident may be so far injured as to 
terminate all sensation and voluntary motion in the lower half of 
the body, the patient seeming lifeless and powerless from the waist 
downward. And yet, by tickling or pinching either foot, the leg of 
the same side may be made to jerk, or even to kick with consider- 
able force ; but, unless the patient is observing his limbs, he is 
wholly unconscious of these movements, which are, therefore, per- 
formed independently of the brain. And they are in no wise due to 
the muscles of the limb; for, if the cord itself become diseased 
below the point of injury, the muscles cease to contract. 

39. Tor the production of this form of nervous action, three 

36. What is necessary in most cases to awaken reflex movements ? In the case of the 
fowl ? Convulsions which follow decapitation ? 

37. Actions in the human body distinct from voluntary efforts ? 

38. Reflex action after injury of the cord ? Why not due to the muscles ? 



200 THE NERVOUS SYSTEM. 

things are requisite — (1) a nerve to conduct messages from the 
surface of the body, one of that variety formerly described as sen- 
sory, but which are now known to be incapable of awakening sen- 
sation ; (2) a portion of uninjured spinal cord, which shall reflect or 
convert impressions into impulses ; and (3) a motor nerve to con- 
duct impulses outward to the muscles. The power of the cord to 
enforce reflex acts resides in the gray matter, into which the reflex 
nerves enter and from which they depart, by means of their pos- 
terior and anterior roots respectively. 

40. The Uses of the Reflex Action. — The reflex activity of 
the cord is exhibited in the healthy body in many ways, but since 
it is never accompanied with sensation, we do not readily recognize 
it in our own bodies. Keflex movements are best studied in the 
cases of other persons, when the conditions enable us to distinguish 
between acts that are consciously, and those that are unconsciously 
performed. For example, if the foot of a person soundly asleep be 
tickled or pinched, it will be quickly withdrawn from the irritation. 

41. Similar movements may be observed in cases where the con- 
sciousness and sensation are temporarily obliterated by disease, or 
by means of narcotic poisons. If the arm of a person who has been 
rendered insensible by chloroform be raised, and then allowed to 
fall, it will be noticed that the limb does not drop instantly, like a 
lifeless member, but a certain amount of rigidity remains in its 
muscles, which resists or breaks the force of its descent. Again, 
when a substance like melted sealing-wax, or a heated coin, falls 
upon the hand, the limb is snatched away at once, even before the 
feeling of pain has been recognized by the brain. When jolted in 
a rapidly moving car, we involuntarily step forward or backward, 
so as to preserve the centre of gravity of the body. 

42. These and similar acts are executed by the same mechanism 
as that previously described in the case of paralysis from an injury 
of the spinal cord. The muscles thus called into play are those 
which are ordinarily under the sway of the will, but which in these 



39. What are the requisites for the production of this form of nervous action ? 

40. Why do we not readily recognize the reflex activity of the cord in our own bodies ! 
How best studied in others? Example ? 

41. Similar movements ? Arm of a person ? Melted wax or heated coin on the hand ? 

42. Result of healthful reflex activity? When may the reflex energy be deficient? 



THE NERVOUS SYSTEM. 201 

cases act through this reflex action of the cord, altogether independ 
ently of the will. A healthful reflex activity produces an elasticity, 
or "tone," in the voluntary muscular system, which in a great 
measure explains the existence in the young and vigorous of a feel- 
ing of buoyancy and reserve power. Its possessor is restlessly 
active, and it may appropriately be said of him, " he rejoiceth as a 
strong man to run a race." But this reflex energy may be deficient. 
This is true when the blood is poor and wanting in its solid ingre- 
dients, or the circulation is feeble; the muscles, then, are flabby 
and weak, and the person himself is said to be " nerveless," or in- 
disposed to exertion. Shivering from cold and trembling from fear 
may, in part, be referred to a temporary loss of tone, resulting from 
a powerful impression upon the brain. {Read Note 6. > 

43. An excess of this activity may also be observed in disease. 
In this condition, the excitability of the cord is unnaturally aroused, 

6. On Nervous Health, or Tone. — "That state of general vigor, 
which we call 'tone,' depends upon the healthy action of the nervous centres. 
It consists in the habitual moderate contraction of the muscles, due to a con- 
stant stimulus exerted on them by the cord, and is valuable less for itself than 
as a sign of a sound nervous balance. Tone is maintained partly by healthful 
impressions radiated upon the spinal cord through the nerves from all parts of 
the body, and partly by the stimulus poured down upon it from the brain. 
So it is disturbed by whatever conveys irritating or depressing influences in 
either direction. A single injudicious meal, a single sleepless night, a single 
passion or piece of bad news, will destroy it. On the other hand, a vivid hope, 
a cheerful resolve, an absorbing interest will restore it as if by magic. For in 
man, these lower officers in the nervous hierarchy draw their very breath ac- 
cording to the bidding of the higher powers. But the dependence of the higher 
on the lower is no less direct. The mutual action takes place in each line. A 
chief condition of keeping the brain healthy is to keep these unconscious 
nervous functions in full vigor, and in natural alternations of activity and re- 
pose. "We see evidence of this law in the delightful effect of a cheerful walk 
after a depressed or irritated state of mind. Every part of the nervous system 
makes its influence felt by all the rest. A sort of constitutional monarchy 
exists within us ; no power in this small state is absolute, or can escape the 
checks and limitations which the other powers impose. Doubtless the Brain 
is King, but Lords and Commons have their seats below and guard their privi- 
lege with jealous zeal. If the ' constitution ' of your personal realm is to be 
preserved intact, it must be by the efforts of each part, lawfully directed to a 
common end. " — Hinton on Health and its Conditions. 



202 THE NERVOUS SYSTEM. 

and frequent and violent movements of the limbs and body, called 
convulsions, are the result The convulsions of young children, 
and the nervous agitation of chorea, or St. Vitus's dance, are reflex 
in character, as are also the symptoms attending poisoning by 
strychnine, and those terrible diseases, tetanus, or "locked jaw," 
and hydrophobia. The severity of the convidsions is not the same 
in all cases of these disorders; but, in those last mentioned, the 
most violent spasmodic movements are provoked by the slightest 
form of irritation — such as the sound of pouring water, the sight of 
any glittering object, the glancing of a mirror, the contact of cool 
air, or even the touch of the bed-clothes. 

44. Another variety of reflex motions takes place in certain in- 
voluntary muscles, and over these the cord exercises supreme con- 
trol. They are principally those movements which aid the perform- 
ance of digestion and nutrition, the valve-action of the pylorus, 
and other movements of the stomach and intestines. In these 
movements the mind shares no part. And it is well that this is so ; 
for, since the mind is largely occupied with affairs external to the 
body, it acts irregularly, becomes fatigued, and needs frequent rest. 
The spinal cord, on the contrary, is well fitted for the form of work 
on which depends the growth and support of the body, as it acts 
uniformly, and with a machine-like regularity. 

45. These operations are not accompanied by consciousness ; for, 
as a general rule, the attention is only called to them when they be- 
come disordered. Many a person does not know where his stomach 
is situated until he discovers its position by reason of a feeling of 
distress within it, produced by giving that organ improper work to 
perform. In this manner the higher and nobler faculties of the 
mind are liberated from the simply routine duties of the body, and 
we are thus left to direct the attention, the reason, and the will to 
the accomplishment of the great ends of our existence. If it were 
otherwise, we could only find time to attend to our ordinary physical 
wants. 



43. Excess of this activity in disease ? Hydrophobia, etc. ? The difference in severity of 
the convulsions? 

44. Another variety of reflex motions? What are they? What is stated of the mind in 
connection with these movements ? 

45. Consciousness in these operations ? Physical wants ? 



THE NERVOUS SYSTEM. 203 

46. The objects of the reflex activity of the cord are threefold. 
In the first place, it acts as the protector of man in his unconscious 
moments. It is his unseen guardian, always ready to act, never 
growing weary, and never requiring sleep. Nor does its faithful 
action wholly cease with the cessation of life in other parts. In the 
second place, it is the regulator of numerous involuntary motions 
that are necessary to the nutrition of the body, Here its actions 
are entirely independent of the brain, and are performed in a secret 
and automatic manner. And, thirdly, it acts as a substitute, and 
regulates involuntary movements in the muscles usually under the 
influence of the will. It thus takes the place of the higher faculties 
in performing habitual acts, and permits them to extend their opera- 
tions more and more beyond the body and its material wants. 

47. The Functions of the Medulla Oblongata.— The pro- 
longation of the spinal cord within the skull has been previously 
spoken of as the medulla oblongata. It resembles the cord, in 
being composed of both white and gray matter, and in conducting 
sensory and motor influences. It likewise gives rise to certain 
nerves, which are here called cranial nerves (from cranium, the 
skull). All except two of these important nerves spring from the 
medulla, or the parts immediately adjoining it ; the exceptions are 
the two nerves taking part in the special senses of sight and smell, 
which nerves have their origin at the base of the cerebrum. 

48. The decussation, or crossing of the motor columns, has been 
previously described, when treating of the direction of the nerve- 
fibres of the cord ; and the singular fact has been alluded to, that 
when one side of the brain is injured, its effects are limited to the 
opposite side of the body. One more fact remains to be observed 
in this connection, namely, this cross action does not usually take 
place in the cranial nerves. Accordingly, when apoplexy, or the 
rupture of a blood-vessel, occurs in the right hemisphere of the 
cerebrum, the left side of the body is paralyzed, but the right side 
of the face is affected ; this is because that part of the body is sup- 
plied by the cranial nerves. 

46. How many objects may the reflex activity be said to have ? State the first. The 
second. The third. 

47. How does the medulla oblongata resemble the cord? 

4S. What final fact is observed in the crossing of the motor columns? 



204 THE NEEVOUS SYSTEM. 

49. A portion of the medulla presides over the important func- 
tion of respiration, and from it arises the pneumogastric nerve, so 
called because its branches serve both the lungs and stomach. 
The feelings of hunger, thirst, and the desire for air are aroused by 
means of this nerve. The wounding of the gray matter of the 
medulla, even of a small portion of it, near the origin of the pneu- 
mogastric nerve, at once stops the action of the lungs and causes 
death. In consequence of the importance of this part, it has been 
termed the "vital knot." We find, also, that its location within 
the skull is exceedingly well protected, it being quite beyond the 
reach of any ordinary form of harm from without. 

50. The Functions of the Cranial Ganglia. — The uses of the 
smaller gray masses lying at the base' of the brain are not well 
ascertained ; and, on account of their position, so remote from the 
surface, it would at first seem well-nigh impossible to study them. 
But, from the results following diseases in these parts, and from ex- 
periments upon inferior animals, they are becoming gradually better 
understood ; and there is reason to believe that eventually the 
physiological office of each part will be clearly ascertained and de- 
fined. It is believed, however, but not absolutely proved, that the 
anterior masses, like the anterior roots of the spinal nerves and the 
anterior columns of the cord, are concerned in the production of 
motion ; in fact, that they are the central organs of that function. 
The posterior gray masses are, on the contrary, supposed to be the 
seat of sensation. 

51. The Function of the Cerebellum. — The function of the 
cerebellum, or " little brain," is the direction of the movements of 
the voluntary muscles. When this organ is the seat of disease or 
injury, it is usually observed that the person is unable to execute 
orderly and regular acts, but moves in a confused manner as if in a 
state of intoxication. Like the larger brain, or cerebrum, it appears to 
be devoid of feeling ; but it takes no part in the operations of the mind. 

52. The Function of the Cerebrum. — The cerebrum, or brain 
proper, is the seat of the mind ; or, speaking more exactly, it is the 

49. The pneumogastric nerve? The feelings aroused by it? The " vital knot?" 

50. The uses of the smaller gray masses at the base of the brain? 

51. Function of the cerebellum ? When it is diseased ? 

52. Where is the seat of the mind ? The subordination of the other organs ? The gray 
matter? 



THE NERVOUS SYSTEM. 205 

material instrument by which the mind acts ; and, as it occupies the 
highest position in the body, so it fulfills the loftiest uses. All the 
other organs are subordinate to it : the senses are its messengers, 
which bring it information from the outer world, and the organs of 
motion are its servants, which execute its commands. Here, as in 
the nervous apparatus of lower grade already considered, the gray 
matter is the element of power ; and in proportion as this substance 
increases in extent, and in proportion to the number of convolutions 
in the hemispheres, do the mental faculties expand. 

53. There have been a few, but only a few, men of distinguished 
ability whose brains have been comparatively small in size — the rule 
being that great men possess large brains. The relative weight of 
the brain of man, as compared with the weight of the body, does 
not, in all instances, exceed that of the inferior animals ; the canary 
and other singing-birds have a greater relative amount of nervous 
matter than man ; but man surpasses all other creatures in the size 
of the hemispheres of the cerebrum, and in the amount of gray sub- 
stance which they contain. — {Read Notes 7 andS.) 

7. The Alliance of Mind and Body. — "The regular routine of our 
daily life is the counterpart of the mental routine. A healthy man wakens in 
the morning with a flush of spirits and energy ; his first meal confirms and 
reinforces the state. The mental powers and susceptibilities are then at a 
maximum ; as the nutrition is used up in the system they gradually fade, but 
may be renewed once and again by refreshment and brief remission of toil. 
Towards the end of the day lassitude sets in, and fades into the deep uncon- 
sciousness of healthy sleep. * * * The influences that affect the body 
extend not only to the grosser modes of feeling, and to such familiar exhibi- 
tions as after-dinner oratory, but also to the highest emotions — love, anger, 
aesthetic feeling, and moral sensibility. ' Health keeps an Atheist in the dark. ' 
Bodily affliction is often the cause of a total change in the moral nature." — 
Bain's Mind and Body. 

8. Large Brains.— "As a rule the size of the brain is proportional to the 
mental development in human beings. The rule is not strictly maintained in 
every instance ; occasionally a stupid man has a larger brain than a clever 
man. But these are only individual exceptions to a prevailing arrangement. 
The following are the brain weights of several distinguished men : 



Cuvier 64 . 5 oz. 

Abercrombie 63 . " 

Daniel Webster ... . 53.5 " 



Lord Campbell 53.5 oz. 

Agassiz 53.4 " 

De Morgan 52.7 " 



1 



53. What is stated of men in connection with the size of their brain ? With the brains of 
other animals? 



206 THE NERVOUS SYSTEM. 

54. It is a singular fact that this cerebral substance is insensitive, 
and may be cut without causing pain. The removal of a consider- 
able quantity of the brain has taken place, as the result of accident, 
without causing death, and without even affecting seriously the 
intellect. A remarkable case of injury of the brain is recorded, in 
which, from the accidental explosion of gunpowder used in blasting 
a rock, the " tamping-iron " was driven directly through the skull 
of a man. This iron rod, three feet and seven inches long, an inch 
and a quarter in diameter, and weighing more than thirteen pounds, 
entered the head below the ear and passed out at the top of the 
skull, carrying with it portions of the brain and fragments of bone. 
The man sustained the loss of sight on one side, but otherwise re- 
covered his health and the use of his faculties. Moreover, disease 
has occurred, compromising a large portion of the brain, without 
impairing the faculties of the mind, when the disease was limited to 
one side only. {Read Note 9. ) 

''The average male brain in Europeans is 49.5 oz. ; the female, 44 oz. 
Among idiots the weights have run from 27 to 8. 5 oz. The brains of the 
insane are below the average of the sane. Tall men, as a rule, hLve larger 
brains than small men. " — Bain's Mind and Body. 

9. The Emotions Influence the Bodily Health. — "The exciting 
emotions which are pleasurable, such as joy and hope, are of a kind that 
seldom tend to a dangerous excess, and may be regarded as exercising generally 
an eminently healthful influence upon the body. Hilarity is a great refresher 
and strengthener of life. Laughter is a wholesome exercise, which, beginning 
at the lungs, diaphragm, and connected muscles, is continued to the whole 
body, ' shaking the sides,' and causing that jelly-like vibration of the frame of 
which we are so agreeably conscious when under its influence. The heart beats 
more briskly, but with a safe regularity of action, and sends the blood to the 
smallest and most distant vessel. The face glows with warmth and color, th« 
e} r e brightens, and the temperature of the whole body is moderately raised 
With the universal pleasurable sensation there comes a disposition of every 
organ to healthy action. When hilarity and its ordinary expression of 
laughter become habitual, the insensible perspiration of the skin is increased, 
the breathing quickened, the lungs and chest expanded, the appetite and 
digestion strengthened, and nutrition consequently increased. The old prov- 
erb, 'Laugh and grow fat,' states a scientific truth. The influence of 
laughter upon the body is recognized by Shakespeare, in his description of the 



54. Sensitiveness of the brain substance ? The removal of a portion of the brain ? State 
the remarkable case mentioned. 



THE NERVOUS SYSTEM. 207 

X55. Impressions conveyed to the hemispheres from the external 
orld arouse the mental operations called thought, emotion, and the 
will. These are the godlike attributes which enable man to sub- 
jugate a world, and afterward cause him to " sigh for other 
worlds to conquer ;" which enable him to acquaint himself with the 
properties of planets millions of miles distant from him, and which 
give him that creative power by which he builds and peoples the 
new worlds of poetry and art. 

56. All these mental acts, and many others, are developed 
through the action of the brain ; not that the brain and the mind 
are the same, or that the brain secretes memory, imagination, or the 
ideas of truth and justice, as the stomach secretes the gastric juice. 
But rather, as the nerve of the eye, stimulated by the subtile waves 
of light, occasions the notion of color, so the brain, called into 
action by the mysterious influences of the immaterial soul, gives rise 
to all intellectual, emotional, and voluntary activities. 

57. The cerebrum, according to our present knowledge of it, must 
be regarded as a single organ, which produces different results, 
according as it is acted upon by the immaterial mind in different 
ways. Kecent investigations, however, seem to prove that the 
faculty of language is dependent upon a small part of the left 
hemisphere of the cerebrum near the temple. At least, in almost 
every instance where this part is diseased, the patient can no 
longer express himself in speech and writing. {Read Note 10. ) 

1 spare Cassius ' — ' Seldom he smiles.' ' To be free-minded and cheerfully dis- 
posed at hours of meat, and sleep, and exercise, is one of the best precepts of 
long-lasting. ' Such is the testimony of Lord Bacon to the favorable influence 
of the pleasurable emotions upon the body. The depressing emotions, such as 
fear, anxiety, and grief, are always fatal to health, and frequent causes of 
death. There is an Eastern apologue which describes a stranger on the road 
meeting the Plague coming out of Bagdad.. 'You have been committing 
great havoc there,' said the traveler, pointing to the city. * Not so great,' 
replied the Plague. ' I only killed one-third of those who died ; the other 
two-thirds killed themselves with fright.' " — The Book of Health. 
10. Mental Exercise Necessary to Perfect Health. — "The im- 



55. Thought, emotion, and will ? What power do they give US? 

56. Are the brain and the mind identical ? 

57. What do we know of the cerebrum and its powers ? 



208 THE NERVOUS SYSTEM. 

58. The Reflex Action of the Brain. — The reflex function of the 
organs within the skull is yery active and important. Like that of 
the cord, it protects the body by involuntary movements, it regulates 
the so-called vegetative acts, and it takes the place of the will in 
controlling the voluntary muscles, when the attention is turned in 
other directions. The reflex power of the medulla governs the acts 
3f respiration, which are absolutely and continuously essential to 
life. Respiration is, as we have seen, partly under the influence of 
the will ; but this is due in part to the fact that respiration is 
indirectly concerned in one of the animal functions — that of 
speech. 

59. Reflex action also occasions coughing and sneezing, whenever 
improper substances enter the air-passages. Winking is an act of 
the same sort, and serves both to shield the eyes from too great glare 
of light, and to preserve them by keeping the cornea moist. Look- 
ing at the sun or other strong light, causes sneezing by reflex action. 
Laughing, whether caused by tickling the feet or by some happy 
thought, and also sobbing, are reflex acts, taking place by means of 
the respiratory muscles. 

60. Certain of the protective reflex movements call into play a 
large number of muscles, as in the balancing of the body when walk- 
pro vement of the memory is a familiar instance of an increase of mental power 
produced by exercise ; and the beating sense of fulness and quickened circula- 
tion in the head induced by intense study or thought, shows that an organic 
process goes on when the brain is in activity, similar to that which takes place 
in the muscular system under exercise. On the contrary, when the organ is 
little used, little expenditure of its power and substance takes place, little blood 
and little nervous energy are required for its support, and, therefore, little is 
sent ; nutrition in consequence soon becomes languid, and strength impaired. 
To all these laws the brain is subject equally as the rest of the body. Frequent 
and regular exercise gives it increased susceptibility of action, with power to 
sustain it, the nervous energy acquiring strength as well as the vascular. Dis- 
use of its functions, or, in other words, inactivity of intellect and of feeling, 
impairs its structure and weakens the several powers which it serves to mani- 
fest. The brain, therefore, in order to maintain its healthy state, requires to 
be duly exercised. " — Barlow on Physical Education. 



58. The reflex function of the organs within the skull? The reflex power of the medulla? 
Respiration ? 

59. What else does reflex action occasion ? Winking ? Other examples ? 

60. Muscles called into play by certain reflex movements ? The somnambulist? 



THE NERVOUS SYSTEM. 209 

ing along a narrow ledge, or on a slippery pavement. The dodging 
motion of the recruit, when the first cannon ball passes over his 
head, is reflex and involuntary. The fact that these involuntary 
reflex acts are performed with great precision, will explain why 
it is that accidents seldom befall the somnambulist, or sleep- 
walker, although he often ventures in most perilous places. 

61- Walking, sitting, and other acts of daily life, become 
automatic, or reflex, from habit : the mind is seldom directed to 
them, but delegates their control to the medulla and spinal cord. 
Thus a person in walking may traverse several miles while absorbed 
in thought, or in argument with a companion, and yet be conscious 
of scarcely one in a thousand of the acts that have been necessary 
to carry his body from one point to another. By this admirable and 
beautiful provision the mind is released from the charge of the 
ordinary mechanical acts of life, and may devote itself to the 
exercise of its nobler faculties. And it is worthy of notice, that 
the more these faculties are used, the more work does the reflex 
function assume and perform ; and thus the employment of the one 
insures the improvement of the other. {Read Notes n and 12.) 

11. Automatic Action of the Brain. — "A large part of our mental 
activity consists of this unconscious work of the brain. There are many cases 
in which the mind has obviously worked more clearly and more successfully in 
this automatic condition, when left entirely to itself, than when we have been 
cudgeling our brains, so to speak, to get the solution. An instance, well 
authenticated, is related of a college student ; he had been attending a class in 
mathematics, and the professor said to his students one day : 'A question of 
great difficulty has been referred to me by a banker — a very complicated ques- 
tion of accounts, which they have not themselves been able to bring to a 
satisfactory issue, and they have asked my assistance. I have been trying, and 
I cannot resolve it. I have covered whole sheets of paper with calculations, 
and have not been able to make it out. Will you try V He gave it to them 
as a sort of problem, and said he would be extremely obliged to any one who 
would bring him the solution by a certain day. This gentleman tried it over 
and over again ; he covered many slates with figures, but did not succeed. He 
was ' put on his mettle,' and determined to achieve the result. But he went 
to bed on the night before the solution was to be given in without having 
succeeded. In the morning, when he went to his desk, he found the whole 



61. What is said of walking and other acts in connection with the office performed by the 
medulla and spinal cord ? 



210 THE NERVOUS SYSTEM. 

62. Effects of Alcohol upon the Brain. — The brain under the 
influence of small and occasional doses of alcohol shows no serious 
changes other than an increased supply of blood to the head. Very 
serious changes, however, result from the habitual use of alcohol ; 
the brain becomes harder and tougher than is natural, and its cell 
elements show a wasting away, its substance appears shrunken, and 
an undue amount of watery fluid fills the cavities in the brain, in 
order to make up the diminished bulk. The blood-vessels of the 
brain are sometimes found to be in a weakened condition, and from 
this various diseased conditions may follow. {Read Note 13.) 

problem worked out and in his own hand. He had risen in the night and un- 
consciously worked it out correctly, as the result proved ; and what is more 
curious still, the process was very much shorter than any of his previous 
trials." — W. B. Carpenter on Unconscious Action. 

12. The Mind Should be Intelligently Cultivated.— "The cultiva- 
tion of the mind should he carried on with judgment, and in due submission 
to the requirements of the body. If study be the duty of the youth, let him 
pursue it diligently, but with such intervals of rest and bodily exertion as may 
maintain good appetite and health. 

" The proportion of hours of study and bodily exercise may vary with the 
degree of mental work, the healthfulness of the room and surrounding air, the 
natural strength of the body, and the degree of health ; but as a general rule 
it may be doubted whether any young person can sit at close study for more 
than two hours at a time without requiring bodily exertion to sustain vital 
action, and rest to recruit the mind. Two hours' mental work, and a quarter 
to half an hour's bodily exercise, will be quite compatible with the greatest 
progress in study. 

"Moreover, it may be doubted whether such a student can work with 
advantage for more than eight hours a day, in addition to the intervals of 
rest, for the issue will not turn on the number of hours devoted to work, but' 
the intensity of the attention given. " — Edward Smith on Health. 

13. Trembling due to Alcohol. — "Another condition is trembling, 
due to alcohol. The hands are shaky, or unsteady, even when at rest, or if 
the hand is held out it is seen to vibrate slightly, or in more advanced condi- 
tion, 'shakes like an aspen leaf.' I have seen this in a spirit-drinker, a bar- 
ber, as almost the only symptom : he worked night and day, in shaving, 
and to 'steady his hand,' partook repeatedly of spirits — at first to relieve 
fatigue and then, because he saw that if he discontinued, his hand was too 
shaky to use the razor. Complete abstinence from alcohol and strong coffee 
quite removed his tremblings and his desire for spirits. " — Dr. W. S. Greenfield. 

62. How is the brain changed by alcohol ? 



THE NERVOUS SYSTEM. 211 

63. Effects of Alcohol on the Mind. — Alcohol produces an 
artificial insanity, in which, according to the quantity taken, the 
various types of mental diseases are distinctly manifest. The per- 
ceptions are bewildered, there is sleeplessness, loss of memory, de- 
lusion, clouded reasoning power, and benumbed moral sense follow- 
ing in the train of alcohol drinking. There is also a monomania 
caused by the prolonged use of alcohol — a craving for drink that 
knows no bounds, and but rarely a cure ; this is dipsomania, or 
thirst-madness. {Read Note 14. ) 

64. The Impairment of the Will. — The direct result of the 
taking of alcohol is seen in the loss of self-control. " The worst 
estate of man is that wherein he loses the knowledge and govern- 
ment of himself." It is in the formation of the drinking habit that 
alcohol too often works the absolute ruin of its devotee, in both body 
and mind. It is apt to be a continuous habit, having for its sequel 
the dethronement of the will. It may be stated, as the rule, that 
after forty years of age, a man who has formed this habit is unequal 
by his own strength of will to abandon it. Many men of fine 
intellectual capacity and amiable qualities have become intemperate, 
and have so continued, as long as their efforts to get free again 
have not been supplemented by outside and enforced restraint.* 

14. Alcohol a Poison of the Intellect. — "In the normal state of a 
man's mind, all the faculties, the imagination, the judgment, the memory, the 
association of ideas, are regulated by another superior faculty, viz. , the atten- 
tion. The attention of the will is the man himself ; it is the ego which, being 
in the full possession of the resources of which it disposes, takes them where 
it will, Avhen it will, to do whatever it pleases. Now in drunkenness, even at 
the very beginning, the will and the attention have disappeared. Nothing is left 
but the imagination and the memory, which, left to themselves, without regu- 
lation and without guides, produce the most irrational results. " — Charles Richet. 

* "Alcohol in small doses super-excites certain intellectual faculties — the 
imagination, the memory, and the association of ideas ; but it paratyzes others, 
especially the will, the reflection, and judgment. Yet, with a stronger dose all 
trace of intelligence disappears. When old Sly is stretched on the ground 
insensible from drink and snoring in the mud, he excites compassion and disgust: 

O monstrous beast ! how like a swine he lies ! 

Grim death, how foul and loathsome is thine image ! " 

Charles Richet, in Revue des Deux Mondcs. 



63. What changes are noticed in the mind? 

64. Give effect of alcohol upon the will. 



212 THE NERVOUS SYSTEM. 

It is for such as these that inebriate asylums have been built 
Other hard drinkers drift into violence and crime, and finally find 
a curative restraint within prison walls. The benumbing effects of 
drinking habits upon the moral being of man is universally known. 
" All delicacy, courtesy, and self-respect are gone ; the sense of 
justice and of right is faint or quite extinct ; there is no vice into 
which the victim of drunkenness does not easily slide, and no crime 
from which he can be expected to refrain. Between this condition 
and insanity there is but a single step," and death, in a worldly 
sense a deliverance, in spite of many an effort to rally, " terminates 
the miserable scene ; one by one lights have been removed from the 
banquet of folly, and the last is now extinguished." {Read Notes 
15 and it.) 

65. An illustration of the disadvantage of drunkenness to the 
moral tone of a community may be drawn from the results of the labors 
of Father Matthew, about forty years ago, as a temperance reformer. 
In the five years — 1838-1842 — the consumption of whiskey in Ire- 
land fell 50 per cent.; the crimes of violence falling from 64,520 to 

15. Drunkenness and Insanity. — " The connection between drunken- 
ness and crime and drunkenness and poverty, is close and unvarying in its 
effect upon society. The remarkable increase of insanity in recent years may 
in part be traced to the use of intoxicating beverages. It has been asserted 
that at least seven-tenths of all the crime and poverty and calamity to the 
people of the United States spring from the abuse of liquors." — Dr. J. E. 
Reeves. 

16. The Effects cf Mild Stimulation.— " Words of caution to young 
men concerning the injurious effects of tobacco, as well as indulgence in wine 
or the pleasures of the table, elicit, in ninety-nine out of one hundred cases, 
the reply, 'It does not hurt me.' Does not hurt you ! Wait and see. In 
years to come, when you ought to be in your prime, you will be a poor, 
nervous, irritable, nerve-dried creature. Your hands will tremble, your head 
will ache, your sleep be fitful and disturbed, your digestion impaired — in short, 
the unnatural and transient pleasure at one end of your life will be more than 
counterbalanced by the discomfort and misery at the other. It is a truth of 
the greatest moment, which ought to be so impressed upon the mind as to be 
always rising up within it, that transgressions of the laws of health, not pun- 
ished at one end of life, are sure to be at the other" — J. R. Black on the Ten 
Laws of Health. 

05. Give results of Father Matthew's work. 



THE NERVOUS SYSTEM. 213 

47,027, and executions from 59 in the first year to 1 in the last 
year. ( Read Note 1 7. ) 

66. The Poisonous Effects of Alcohol. — Alcohol is, in the 
main, a narcotic poison in its effects upon human beings, although 
the visible results vary immensely according to the quantity taken. 
If a sufficient quantity is taken to cause any visible result, a condi- 
tion known as stimulation is observed.* If an extremely large 
dose is taken, a state of stupor follows, and death has been known 
to result in some cases. Between these two extremes there may be 
a variety of manifestations. As a stimulant, it appears to many to 
have a kindly action, to cause a glow and sense of warmth, to in 
crease muscular activity, and to make the mind and organs of speech 
more nimble. Alcohol is not the only narcotic poison that exercises 
this influence, which is not kindly, but is in fact the first indica- 

17. Alcohol and Crime. — " Thirty years of judicial experience have 
taught me that of the crimes which judges are called upon to try, and 
upon which sentences of the law are pronounced, more than eight-tenths of 
them involving any degree of violence in their character are directly traceable 
to the liquor shops. How often have I had young men look up at me when 
I asked them what they had to say why the sentence of the law should not be 
pronounced, declare, ' I should never have done this crime if it were not for 
drink. Rum was my ruin ; rum struck the blow, and not my hand, that 
killed the man for whose death I am tried ; rum has caused me to beat my 
wife, and injure my helpless child, and to do the act which now confines me to 
a prison.' " — Judge Noah Davis. 

* "Suppose, for instance, you measure your muscular strength with a 
' health lift ' or dynamometer (by which muscular exertion can be accurately 
measured), and then take some of the drink, in the strength-inspiring power 
of which you have most confidence, and when you are most exhilarated by it, 
and feel as if you could shoulder a large fragment of Mount Olympus, measure 
your strength again. The drink has fooled you, that is all. You felt that you 
were stronger than natural ; you find that the narcotic has been true to its 
paralyzing nature, and that you are weaker. Then, after a time, when the 
drug has spent itself, and reaction (so called) comes on, and you feel weak and 
prostrated, measure your strength once more. Fooled again ; the stuff has 
fooled you twice. When you felt yourself strong you were weak, and now when 
you feel yourself weak, you find yourself stronger — your natural strength is 
returning, and what you have called reaction is in reality recovery from the 
weakening effects of the narcotic." — Dr. A. F. Kinne. 



66 Poisonous effects of alcohol 9 



> 



214 THE NERVOUS SYSTEM. 

tion of a paralysis of a portion of the nervous system. Most of the 
habitual takers of alcohol freely admit that they are injured by it 
in one way or another, and still they continue in their indulgence. 
In such cases the mental balance is already lost ; for a person to 
covet that which he knows to be hurtful to him, is manifestly not 
the sign of a sound mind. {Read Note 18.) 

67. Tobacco and its Effects. — Tobacco, familiarly known as 
; 'the weed," is an annual plant said to be a native of America. It 
grows to the height of several feet, with leaves of a pale green 
color. These leaves, when dried, are made into cigars, chewing- 
tobacco, and snuff, which are extensively used throughout the 
civilized world. 

68. Tobacco as a Poison. — Tobacco is a poison to the young, 
and is far more hurtful to the adult than is generally supposed. It 
may be stated, as a ride, that there are few persons who use it 
habitually that do not suffer injury from it. The injury is mainly 
caused by what is known as " nicotine," one of the narcotic poisons, 
and particularly prominent in tobacco. Some of the effects of its 
limited use are nausea, vomiting, vertigo, and weakness ; and its 
prolonged use, by those who are sensitive to it, often results in 
convulsions and other like symptoms, together with an irritability 
and weakened condition of the heart, known to physicians as the 
"tobacco-heart." 

18. " Here is a company of 'jolly good fellows,' all standing on their feet, 
their faces red and radiant, and all swinging their arms and talking at once. 
These men have been taking alcohol, and, surely, you will say, it has stimu- 
lated them. But if you will attend for a moment to what they are saying, you 
will see that there is no true brain-stimulation about it. We shall be reminded 
rather of what Addison says of the difference between the mind of the wise 
man and that of the fool : ' There are infinite, numberless extravagancies, and 
a succession of vanities which pass through both. The great difference is that 
the first knows how to pick and cull his thoughts for conversation, by sup- 
pressing some and communicating others ; whereas the other lets them all 
indifferently fly out in words. ' The case with these revelers is precisely this. 
The poison which they have taken has paralyzed their conservative faculties, 
and the talking propensity is running on without anything to hold it in check 
and regulate it" — Dr. A. F. Kinne- 



67. Describe the tobacco plant. 

68. What is its effect upon the nerves ? 



THE NERVOUS SYSTEM. 215 

69. Effects on the Young. — Of the pernicious influence cf the 
use of tobacco upon the young, the testimony of the Naval and 
Military Academies of the country is very decided. It has at times 
been allowed in both institutions, but at present it is forbidden, 
on the ground that its use is attended with serious damage to 
health. It is stated that its prohibition at the Naval Academy in 
1881 was received with unanimous approval by the officers in 
charge, and with " great joy by many of the cadets." Tremor of 
the muscles, caused by smoking, was very noticeable in the draw- 
ings that form so important a part of the cadets' work. A teacher 
of drawing, of fourteen years experience, has said that he can 
always tell from the character of the lines in the drawings, whether 
or not the pupils used tobacco.* Its avoidance has resulted in the 
reduced number of minor ailments that swelled the sick-list in years 
when its use was unrestricted. Athletes and other persons who 
engage in running matches and the like, are commonly not allowed 
to use either alcohol or tobacco while they are "in training;" their 
use interferes with the fullest development of muscular strength. 
{Read Note 19.) 
1 ~ 

* "Prof. Mantegazza, of Florence, Italy, a distinguished sanitarian and phy- 
sician, testifies that ' Tobacco is never necessary ; it is always hurtful to boys 
and young men, to weak people, and those disposed to consumption. * * * * 
All good citizens should try to put a stop to the general invasion of tobacco, 
which threatens to involve the whole of Europe in a dense cloud of smoke, 
which poisons even those who do not smoke. ' " 

19. "The end of all science is to secure long life and good health to the 
individual and the race, and it ought to be a part of the rational creed of every 
good man and woman to abjure the use of tobacco, and keep others from fall- 
ing into the vice." — Dr. C. E. Drysdale. 

"Of tobacco, Franklin said that he could not think it had ever done much 
good in the world, since he never knew a person who used it habitually whc 
would recommend another to do the same." 

"Tobacco is certainly not a food for man, nor has it much value as a medicine. 
The tobacco-worm is the only animal known to thrive upon it. " — F. E. Hamilton. 

"An illustration of the depressing influence of tobacco is given by Dr. Jacob 
Bigelow, who states that soldiers, when wishing to shirk duty and get on the 
sick-list, sometimes succeed in bringing on the symptoms of alarming sickness 
by wearing a piece of tobacco under each arm-pit. The skin absorbs sufficient 
of the poison to affect the system to a marked degree." 



69. Give the effects of tobacco upon the young ? 



216 . THE NERVOUS SYSTEM. 

70. Cigarette-Smoking. — This form of taking tobacco is inju- 
rious in two particulars, that do not apply to the other forms. 
The smoker of cigarettes, either voluntarily or involuntarily, takes 
into his lungs a very large amount of smoke, and with it that 
hurtful element, carbonic oxide. Again, there is an excessive 
amount of adulteration of the tobacco in cigarettes; and one sub- 
stance, opium, is largely so used and is extremely injurious. 

71. Snuff- Taking. — In addition to the hurtful effects of tobacco 
generally, snuff-taking is notoriously injurious to the senses of smell 
and taste, and to the voice. 

72. Narcotics. — The term narcotic is applied to different sub- 
stances derived chiefly from the vegetable kingdom, which have 
the wonderful property of quieting pain and causing sleep. Next 
in importance to alcohol, which belongs to the narcotics, are opium 
(and its preparations), chloral hydrate, hasheesh and chloroform. 

73. Opium. — Opium is the thickened juice of the poppy-plant 
of India, and is commoidy regarded as the most important of the 
narcotics. Its active principle is morphine, which gives the sooth- 
ing property to laudanum, paregoric, and Dover's powders. It is 
also used in nostrums to put infants to sleep : but unwisely used, 
often brings on a sleep that knows no waking. 

74. Effects of Opium. — Opium is particularly injurious to 
the young, even small doses sometimes producing alarming symp- 
toms. Upon adults the external effects are not as noticeable as are 
those of alcohol, but the mind is more deeply stirred and the flow of 
ideas more copious. 

75. Danger from Opiates. — The use of opium for relieving 
pain has been known for hundreds of years. The enchanting 
sense of relief to suffering wrought by opiates leads to the mor- 
phine habit, commonly called opium-eating. It will be seen, there- 
fore, why such great care is exercised by physicians in administering 
opiates, lest their patients afterward fall into the habit of taking 
them without medical advice. {Read Note 20. ) 

20. "The opium-eater loses none of his moral sensibilities or aspirations ; 
he wishes and longs as earnestly as ever to realize what he believes possible, 

70. What is said of cigarette-smoking ? 73. What is opium ? 

71. Snuff-taking? 74. What are the effects of using opium ? 

72. What do you understand by narcotics ? 75. What the danger? 



THE NERVOUS SYSTEM. 217. 

76. Physiological Effects of Opium. — The frequent use of 
opium disturbs and weakens the stomach as well as the other 
digestive organs ; hence we invariably find the opium-eater to be 
a lean, yellow, sallow person. His muscular and mental powers 
are impaired, and his will is terribly enfeebled. This dreadful 
habit can be broken only with unspeakable suffering to its victim. 

77. Chloral Hydrate. — Chloral hydrate, commonly called 
chloral, is produced from alcohol; but its power as a sedative 
was not generally known until within the past twenty years. 
It also is a destroyer of appetite as well as of digestion, unless 
prescribed in proper doses, and the unfortunates once given over 
to it find themselves unable to sleep without its continued use. 
It should never be taken except under the direction of a physician. 

78. Hasheesh. — Hasheesh, the juice of Indian hemp, is said to 
be used by millions of the inhabitants of Asia. It is not much 
known in the western countries. In the East the excitement caused 
by its use takes the form of furious madness, leading its victim to 
commit acts of violence and murder. Hence the term " hasheeshers " 
in our language has come to be synonymous with assassins. {Read 
Note 21.) 

79. Chloroform. — Chloroform, another product from alcohol, is 

and feels to be exacted by duty ; but his intellectual apprehensions of what is 
possible infinitely outruns his power, not of execution only, but even the power 
to attempt. He lies under the weight of incubus and nightmare ; he lies in 
sight of all that he would fain perform, just as a man forcibly confined to his 
bed by the mortal languor of a relaxing disease, who is compelled to witness 
injury and outrage offered to some object of his tenderest love ; he curses the 
spells which chain him down from motion ; he would lay down his life if he 
rnight but get up and walk ; but he is powerless as an infant, and cannot even 
ittempt to rise. " — De Quincey's Confessions of an Opium-Eater. 

21. "As everybody knows, the intoxication caused by alcoholic liquors, by 
hasheesh, by opium, after a first period of excitement, brings about a notable 
impairment of the will. The individual is more or less conscious of this ; 
other persons see it more clearly. Soon — especially under the influence of 
alcohol — the weakening of the will becomes excessive. The extravagances, 
violences, and crimes committed in this state are innumerable." — Dr. T. Mbot 



76. What effect upon the system ? 

77. What do you know of chloral hydrate ? 

78. What is hasheesh ? Its use ? 

79. Chloroform? Its use? 



10 



218 THE NERVOUS SYSTEM. 

used by inhalation when surgical operations are to be performed. 
As it is very powerful and subtle in its action, the unskillful use 
of it is dangerous in the extreme. The habit of taking chloroform 
by those who are great physical sufferers, or whose constitutions 
have been wrecked by the use of other narcotics, should be dis- 
couraged. It too often happens that the career of such is short, 
for the drug may easily be taken in excess and so cause death. 

80. Sleep Produced by Narcotics. — Opium and the opiates 
have the power of quieting the activity of the brain, and of com- 
pelling sleep. This may be a blessed action if skilfully applied 
by the physician, but not so applied it is the source of infinite peril. 
The sleep so caused differs from natural, restful slumber, especially 
in the fact that the after effects are commonly depressing and 
disturbing to the brain to the extent of being harder to bear 
than the wakefulness on account of which the drugs are taken. 
Very young persons are especially subject to injury by sleep- 
producing medicines ; and many are the deaths that have been 
caused among infants by the giving of " soothing syrups," " cordials," 
and "anodynes," that are so freely made and sold for the purpose of 
compelling sleep. 

81. Results of the Use of Narcotics. — The use of any of these 
narcotics, without proper medical advice, is their abuse. In this 
way they become powerful for harm. They are no longer remedies, 
but poisons. Self-prescribed, they have a thousand times been the 
instrument of unintentional suicide. {Read Note 22.) 

22. The Narcotics and Digestion. — "The habitual use of opium and 
other narcotic drugs is unfriendly to digestion, leading to nausea and a 
distaste for wholesome food. The vigor of the organs of digestion is 
impaired. 

44 The disturbing effects of tobacco, in producing nausea and vomiting, is 
well known, and is almost the invariable experience of all beginners in the use 
of that substance ; loss of appetite is a very frequent result of the habitual 
use of it." 

80. What kind of sleep produced by narcotics? 

81. What the results of the use of narcotics ? 



THE NERVOUS SYSTEM. S^~ 219 



QUESTIONS FOR TOPICAL REVIEW. 

PAGE 

1. State fully what is meant by the term vegetable function 181 

2. To what does man owe his position as the head of the animal creation ? 182 

3. What can you state on the subject of special organs for separate functions ? 182 

4. Describe, as fully as you can, the structure of the nervous system 182, 183 

5. Describe the brain, its location, size, shape, and structure 183 

6. Describe the brain proper, or cerebrum 185 

7. Describe the little brain, or cerebellum 187 

8. Describe the spinal cord 188 

9. What are the spinal nerves, and how are they arranged ? 189 

10. What is the character and substance of their tissues ? 189 

11. State and illustrate how the nerve-fibres perform their office 190 

12. Describe the sympathetic system of nerves 190, 191 

13. State the properties of nervous tissue, and illustrate , 192 

14. Explain the functions of the nerves 194 

15. What is meant by transient paralysis of a nerve ? Illustrate 195 

16. What can you state of the rate of message-motion along a nerve ? 196 

17. What are the functions of the spinal cord? 196 

18. State what you can of the form of paralysis known as paraplegia 196 

19. What experiments, with results, upon the spinal cord are noted ? 197 

20. Give the direction of fibres of cord 197 

21. How does the left side of brain feel pain in right hand ? 198 

22. What is understood by the reflex action of the cord ? 198 

23. What experiments are mentioned to prove this power of the cord ? 198 

24. What are the uses of the reflex action of the cord ? 200 

25. What is the medulla oblongata and its function? 203 

26. What can you state of the functions of the cranial ganglia ? 204 

27. What are the functions of the cerebellum ? 204 

28. What is the function of the cerebrum? 204 

.29. In what way does the size of the brain generally indicate the character ? 205 

30. What facts show that the gray substance of the brain is insensitive ? 206 

31. Upon what does the faculty of language seem to depend ? 207 

32. Of what importance is the reflex action of the brain ? 208 

33. In what ways is this importance made manifest ? 209 

34. Give the effects of alcohol upon the brain 210 

35. How does it affect the mind? 211 

36. What is said of the effect upon the will? 211 

37. How is the whole system affected ?. 213 

38. What is said of tobacco ? 214 

39. Define and illustrate the term narcotic 216 

40. Give the statement regarding opium 216 

41. State what you can of chloral 217 

42. What is hasheesh and its effect? 217 

43. What is said of chloroform? 218 

44. Give general results of use of narcotics r .._„ 218 



CHAPTER X. 

The Special Senses. 

The Production of Sensations — Variety of Sensations — General Sensibility — Pain 
and its Function — Special Sensation, Touch, Taste, Smell, Sight, and 
Hearing — The Hand, the Organ of Touch — The Sense of Touch — Delicacy 
of Touch — Sensation of Temperature and Weight — The Tongue, the Organ 
of Taste — The Nerves of Taste — The Sense of Taste and its Relations with 
the other Senses — The Influence of Education on the Taste — The Nasal 
Cavities, or the Organs of Smell — The Olfactory Nerve — The Uses of the 
Sense of Smell — The Sense of Sight — Light — The Optic Nerve — The Eye- 
ball and its Coverings — The Function of the Iris — The Sclerotic, Choroid, 
and Retina — The Tears and their Function — The Movements of the Eye- 
ball — The Function of Accommodation — The Sense of Hearing and 
Sound — The Ear, or the Organ of Hearing — The External, Middle, and 
Internal Ear. 

1. Production of Sensations. — We have already seen that the 
true centre of sensation is some organ within the skull, probably 
among the gray masses at the base of the brain ; but the mind never 
perceives impressions at that point ; on the contrary, it always refers 
them to the external organs of sensation. Hence, it is convenient 
to say that those outer parts possess the property of sensibility. 
For instance, we say that we hear with the ear, taste with the 
tongue, and feel with the fingers. That this is not the exact truth 
is proved by the fact that, whenever the nerve connecting one of 
these organs with the brain is severed, it at once loses its capacity 
for sensation. 

2. Consciousness, another faculty of the brain, is necessary to 
complete a sensation. During sleep, and in other unconscious 
states, the usual impressions are presented to the ear, the nose, and 



1. True centre of sensation ? Place of the mind's impressions ? What is it convenient to 
say ? What further is stated ? 

2. Consciousness? During sleep? In profound insensibility ? 



THE SPECIAL SENSES. 221 

the skin; but they fail to excite sensations, because the nerve-centres 
are inactive. In profound insensibility, from chloroform or ether, a 
limb may be removed without occasioning the least feeling. 

3. Variety of Sensations. — All animals have some degree of 
sensibility. It is, of course, feeble and indistinct in the lower 
forms of life, but increases in power and variety as we ascend the 
scale. In the earth-worm, the nervous system is very simple, the 
sensibility being moderate and alike in all parts ; hence, if its body 
be cut into two pieces, each piece will have the same degree of feel- 
ing as before. As we approach man, however, the sensations 
multiply and become more acute ; the organs are more complex, and 
special parts are endowed with special gifts. These special organs 
cannot be separated from the rest of the body without the loss of 
the functions they are designed to exercise. 

4. The lowest form of sensation — that of simple contact — is pos- 
sessed by the lowest of the animal creation. The highest forms are 
those by which we are enabled to know the properties of external 
objects, such as shape, size, sound, and color. A variety of means 
of communicating with the outer world is the necessary possession 
of a high intelligence. Sensations are modified by use. They 
become more acute and powerful by moderate exercise, or they are 
dulled by undue excitement. The former is shown by the acute 
hearing of the Indian, by the sharp sight of the sailor, and by the 
delicate touch of the blind. The latter is exemplified by the 
impaired hearing of the boiler-maker, and the depraved taste of him 
who uses pungent condiments with his food. Again, impressions 
habitually presented may not be consciously felt, as is the case with 
the rumbling of carriages in a neighboring street, or the regular 
ticking of a clock. All sensations become less vivid with the 
advance of age, especially hearing and vision. 

5. General Sensibility. — There is a property possessed by nearly 
all parts of the human body which we call general sensibility. We 
have recently seen that the brain is wholly insensitive, and may be 
cut or pinched without pain. The same is true of the nails, hair, 

3. Sensibility in animals ? In the earth-worm? In man? 

4. The lowest form of sensation ? The highest? Sensations, how modified? What further 
can you state as to habitual impressions? 

5. General sensibility? What have we seen as regards the brain? Of what other 
structures is the same true? 



222 THE SPECIAL SENSES. 

the scarf-skin or external covering of the body, and a few other 
structures. In these parts no nerves are found. On the other 
hand, the sensibility of the true skin, and of mucous membranes, as 
of the eye and nose, is exquisite, these organs having a large supply 
of sensory nerve-fibres. The bones and tendons have less of these 
fibres, and are only moderately sensitive. 

6. The sensibility of any part of the body, then, depends upon 
the number of nerves present; and, as a rule, the nervous supply is 
proportional to the importance of the part, and to its liability to 
injury. When, therefore, a surgical operation is performed, the 
most painful part of it is the incision through the skin — the mus- 
cles, cartilage, and bone being comparatively without sensation. 
Hence, if we could benumb the surface, certain of the lesser opera- 
tions might be undergone without grept inconvenience. This is, in 
fact, very successfully accomplished by means of the cold produced 
by throwing a spray of ether, or of some other rapidly evaporating 
liquid upon the part to be cut. 

7. Tickling is a modification of general sensibility. At first it 
excites a pleasurable sensation, but this soon passes into pain. It 
is only present in those parts where the sense of touch is feeble. 
But all impressions are not received from without ; there are, also, 
certain internal sensations, as they are called, which depend upon 
the condition of the internal organs, such as appetite, hunger, 
thirst, dizziness when looking down from some lofty position, 
drowsiness, fatigue, and other feelings of comfort or discomfort. 
General sensibility, whether of the internal or external organs of 
the body, chiefly depends upon the sensory fibres of the spinal 
nerve. The face, however, is supplied by the sensory cranial 
nerves. The sympathetic system has a low grade of feeling in 
health, but disease in the parts served by it arouses an intense 
degree of pain. 

8. The Sensation of Pain. — What then is pain? Is it iden- 
tical with ordinary sensibility 1 ? There seems to be some necessary 
connection between the two feelings, for they take place through 

6. The cause of sensibility? Painful part in a surgical operation? Benumbing the 
surface ? How done by ether? 

7 Tickling? Internal sensations? The nerves of general sensibility? 
$. Connection between pain and sensibility ? 



THE SPECIAL SENSES. 223 

the same channels, and they are alike intense in the same situ- 
ations. But sensibility habitually contributes to our sources of 
pleasure — the very opposite of pain ; hence, these feelings cannot be 
identical. 

9. Pain must, therefore, be a modification of the general sensi- 
bility which follows an excessive degree of excitement of the 
nerves, there being a natural limit to the amount of stimulation 
which they will sustain. So long as this limit is observed, the 
part excited may be said to be simply sensitive; but when it is 
exceeded, the impression becomes painful. This difference between 
sensibility and pain is well shown by the effects of sunlight upon 
the eye. The indirect illumination of the sun arouses only the 
former feeling, and is indispensable to our comfort and existence, 
while the direct ray received into the eye occasions great pain. 

10. The Uses of Pain. — The dread of pain is a valuable moni- 
tor to the body. It puts us on our guard in the presence of danger, 
teaches moderation in the use of our powers, indicates the approach 
of disease, and calls attention to it when present. The word dis- 
ease, in fact, according to its original use, had reference simply to 
the pain, or want of ease, which commonly attends disordered 
health. When we observe the serious mishaps which occur when 
sensibility and pain are absent, we cannot fail to appreciate its 
value. For example, a paralytic, in taking a foot-bath, forgets to 
test its temperature, and putting his limbs into water while it is too 
hot, is severely scalded without knowing it. 

11. A traveler, overcome by cold and fatigue, lies down and falls 
asleep near a large fire, and when he is aroused in the morning, it 
is discovered that one of his feet has been insensibly destroyed. A 
grain of sand, lodging in an insensitive eye, may cause inflamma- 
tion, and even the loss of sight. If intense light were not painful 
to the eye, many a child would innocently gaze upon the glories of 
the sun to the ruin of his sight. 

12. Pain is, indeed, a present evil, but its relations with the 
future prove its mission merciful. Painful impressions cannot be 

9. Explain the difference between pain and sensibility. 

10. Dread of pain ? How may its value be appreciated ? Example ? 

11. The case of the traveler? Grain of sand ? The sun and child? 

12. Mission of pain ? Painful impressions compared with those of pleasure ? 



224 THE SPECIAL SENSES. 

recollected from past experience, and they cannc :t be called into 
existence by the fancy. Considered in the light of results, pain 
has a use above that of pleasure; for, while the immoderate pursuit 
of the latter leads to harm, the tendency of pain is to restrict the 
hurtful courses of life, and in this manner to protect the body 

13. The relations of pain to pleasure are thus described by the 
eminent physiologist, Magendie : — "By these sensations Nature 
induces us to concur in the order which she has established among 
organized beings. Though it may appear like sophistry to say that 
pain is the shadow of pleasure, yet it is certain that those who have 
exhausted the ordinary sources of pleasure have recourse to the 
causes of pain, and gratify themselves by their effects. Do we not 
see in all large cities, that men who are debauched and depraved 
find agreeable sensations where others experience only intolerable 
pain?" {Read Note I.) 

14. As to painful sensation among the inferior animals, the plan 
of Nature seems to be, that the higher the intelligence of the crea- 

1. Pain is "Nature's Harbinger of Mischief." — "It must, there- 
fore, be evid ?,nt that pain is, under certain circumstances, really beneficial. It 
is often a great boon to have a sensitive stomach ; for those who suffer pain 
after food are less apt habitually to err in diet, and thus to become dyspeptic 
or gouty, than those whose organs receive everything uncomplainingly. Pain 
in the stomach is frequently due (in well-to-do people) to the fact that they 
won't work and will eat ; not that the stomach itself is weak (as they think), 
but that the supply of food being greater than the demand, the system becomes 
overstocked. In dyspepsia the cause is very often far away, and the stomach 
is no more the cause of the malady than the big toe is of the gout ; but if the 
stomach gave no signs of perturbation, the evil would be allowed longer to 
exist unnoticed. We should always give early attention to pain, and discover 
its causes before they become too complex to be unraveled, and before the 
derangement which its presence indicates becomes permanent. The follow- 
ing incident well illustrates the extent to which pain may be dependent on 
fancy: 'A butcher was brought into a druggist's from the market-place oppo- 
site, laboring under a terrible accident. The man, on trying to hook up a 
heavy piece of meat above his head, slipped, and the sharp hook penetrated 
his arm so that he himself was suspended. On being examined, he was pale, 
almost pulseless, and expressed himself as suffering acute agony. The arm 
could not be moved without causing excessive pain, and in cutting off the 

13. What ioes Magendie say of the relation of pain to pleasure ? 

14. The law of Nature as regards painful sensations among animals ? 



THE SPECIAL SENSES, 225 

fcure, and the more complete its power of defence, the more acute is 
its sensibility. We infer, therefore, that animals low in the scale 
of existence, and helpless, are not very liable to suffer pain. 
sj 15. Special Sensation. — The sensations of simple contact and 
pain are felt by nearly all parts of the system, whether external 
or internal, and are the necessary consequence of the genera] 
sensibility; but, so far as the objects which surround us are con- 
cerned, these impressions are vague and passive in character, and 
inform the mind of none of the properties or powers of these 
objects. Besides these feelings, therefore, man is endowed with 
certain special sensations, which are positive and distinct in charac- 
ter, and which he can call into exercise at will, and employ in 
the pursuit of knowledge. For reasons relating to the original 
constitution of the body, these sensations are to be regarded as 
modifications of the general sensibility already alluded to, con- 
structed with special reference to the different forces of Nature of 
which we have any knowledge, such as heat, motion, gravity, sun- 
light, and the like. {Read Note 2.) 

sleeve lie frequently cried out ; yet, when the arm was exposed, it was found 
quite uninjured, the hook having only traversed the sleeve of the coat!' The 
sensation here was perfectly real, but originated in a change of the brain and 
nerves, instead of in the external senses." — Notes on Pain. 

2. The Mutual Relations of the Special Senses. — "A blind man 
attempting to express his notion of scarlet, said it resembled the sound 
of a trumpet. "We are constantly reminded of the impressions of one 
sense by the operations of another. To my ear the bass note in music 
is what a dull black is to the eye. The reverberations of deep thunder seem 
like boulders with worn angles — with profiles blunt and irregular, as if drawn 
by the jerking pencil of the lightning ; and one who never had the pleasure of 
seeing stars from a blow on the head, may get a tolerably correct idea of that 
kind of galaxy by snuffing at a bottle of volatile salts. 

"Language is full of effort to report the impressions of one sense by the 
symbols of another. We say that an apple is sweet, that a rose is sweet, a 
face is sweet, a strain of music is sweet, and love is sweet, not to mention the 
saccharine reaction of the 'uses of adversity.' Here taste, smell, sight, hear- 
ing, and a social sentiment use the same word for that pleasurable sensation 
experienced by the mind through each distinctive organ. We assist the organ 
of one sense by that of another. We open the lips and part the teeth a little 

15. The sensation of contact and pain ? Special sensations of man ? How regarded ? 



226 THE SPECIAL SENSES. 

16. These distinct and active faculties are termed the special 
senses, and are five in number, viz., Touch, Taste, Smell, Sight, and 
Hearing, for the exercise of these senses, special organs are fur- 
nished, such as the hand, the tongue, the nose, the eye, and the 
ear. The manner in which the nerves of special sense terminate 
varies in the case of each organ, so that each is adapted to one set 
of sensations alone, and is incapable of perceiving any other. Thus 
the nerve of hearing is excited by the waves of sound, and not by 
those of light, while the reverse is true of the nerve of sight; and 
the nerve of smell can appreciate neither of them, being capable 
only of taking cognizance of the odorous properties of bodies. 
{Read Note 3. ) 

17. By some writers six senses are accorded to man, the addi- 

when we are eager to hear \ we listen and turn the eyes' attention inward when 
we would detect a delicate taste, or remember a faded impression. 

" But this mutual accommodation of the senses is not so marvelous as it 
may seem, when we remember that the whole five, six, or seven, as you please, 
are but one power of nervous perception, specialized into a variety of functions, 
differentiated, as the learned say, that we may have more perfect work by a 
division of labor. The same necessity which developed nerve-contact into 
sight on the one hand and hearing on the other, might also express through 
one of these the sensations proper to the other, when the other was wanting. 
Seal up the eyes of a bat, say the naturalists, and let it loose in a room crossed 
with wires in every direction, and he will fly clear of them all, as if he had 
other means of perception as sensitive as the optic nerve. 

" Laura Bridgman, with neither sight, hearing, nor smell, could detect the 
presence of a stranger in the room, without contact. Her mind then must 
have as distinct an image of every person as we have, yet not one of what we 
call our senses could go to the making up of that image. It could not be form 
as we know it, nor a voice, nor an odor, but it was itself other than all, excit- 
ing emotions of love, or hate, gratitude or repugnance, and the thought it 
excited must have had shape, though it is not easy to imagine how." — The 
Schoolmaster. 

3. Variation in Structure in the Nerves of Special Sense. — 
"While in the more intellectual senses — Sight, Hearing, and Touch — the 
nerves have their protecting and isolating sheaths corresponding with the dis- 
tinctness and separateness of the parts of the impression, in Smell, the nerves 
are a plexus of unsheathed fibres, corresponding with the fusion of the odorous 
impression into one whole, without distinction of parts." — Herbert Spencer. 



16. What are the special senses ? Special organs for them ? 

17. What is said in relation to one more than the five senses? 



THE SPECIAL SENSES. 227 

tional one being either the sense of temperature — for, as we shall 
presently see, this is not the same as touch — or, according to others, 
the muscular sense by which we are enabled to estimate the weights 
of bodies. The latter also differs in some respects from the sense 
of touch. 

18. Organs of Touch. — The sense of touch is possessed by 
nearly all portions of the general surface of the body, but it finds 
its highest development in the hands. The human hand is prop- 
srly regarded as the model organ of touch. The minute structure 
of the skin fits it admirably for this form of sensation; the cuticle, 
or scarf-skin, is fine and flexible, while the cutis, or true-skin, con- 
tains -multitudes of nerve-filaments, arranged in rows of papillae or 
cone-like projections, about one one-hundredth of an inch in length. 
It is estimated that there are 20,000 of these papillae in a square-inch 
of the palmar surface of the hand. Now, although the nerves of 
the cutis are the instruments by which impressions are received and 
transmitted to the brain, yet the cuticle is essential to the sensation 
of touch. This is shown by the fact that whenever the true-skin 
is laid bare, as by a burn or blister, the only feeling that it experi- 
ences from contact is one of pain, not that of touch. 

19. The office of the cuticle is thus made evident ; it is to shield 
the nerve-filaments from direct contact with external objects. At 
the tips of the fingers, where touch is most delicate, the skin rests 
upon a cushion of elastic material, and receives firmness and perma- 
nence of shape by means of the nail placed upon the less sensitive 
side. Besides these favorable conditions, the form of the arm is 
such, and its motions are so easy and varied, that we are able to 
apply the test of touch in a great number of directions. The 
slender, tapering fingers, with their pliant joints, together with the 
strong opposing thumb, enable the hand to grasp a great variety of 
objects; so that, great as are the delicacy and grace of the hand, it 
is not wanting in the elements of power. 

20. Its beauty and adaptation to the wants of man have made 
the hand an attractive theme for philosophers. They do not, how- 
ever, always agree in their conclusions. One has the opinion that 

18. The sense of touch, how prevalent? What is said of the hand ? 

19. Office of the cuticle? Tips of the fingers? The fingers with thumb ! 

20. What special importance is attributed to the hand? ....... 



228 THE SPECIAL SENSES. 

man has acquired his intelligence and achieved his place as " lord 
of creation," because he has this organ. Buffon, in effect, declares 
that with fingers twice as numerous, and twice as long, we would 
become proportionally wiser; but Galen long ago took a more 
reasonable view, when he taught that " man is the wisest of ani- 
mals, not because he possesses the hand, but because he is the 
wisest, and understands its use; for his mind, not his hand, has 
taught him the arts." Another has well said, that " no one can 
study carefully the human hand and fail to be convinced of the 
existence of the Deity." 

21. The Sense of Touch. — Touch is the simplest of the 
senses. It is that which the child first calls into exercise in 
solving the early problems of existence, and it is that which is in 
the most constant use throughout life. We are brought by the 
touch into the most intimate relations with external objects, and by 
it we learn the greater number, if not the most important, of the 
properties of these objects, such as size, figure, solidity, motion, and 
smoothness or roughness of surface. 

22. The sense of touch assists the other senses, especially that of 
sight, giving foundation and reality to their perceptions. Without 
it, the impressions received by the eye would be as vague and 
unreal as the figures that float through our dreams. A boy who 
had been blind from birth, at the age of twelve years received sight 
by means of a surgical operation ; at first, he was unable to distin- 
guish between a globe and a circular card of the same color before 
he had touched them. After that, he at once recognized the differ- 
ence in their form. He knew the peculiarities of a dog and a cat 
by feeling, but not by sight, until one day, happening to take up 
the cat, he recognized the connection of the two sorts of impres- 
sions — those of touch and sight; and then, putting the cat down, he 
said: " So, puss, I shall know you next time." 

23. Of all the senses, touch is considered the least liable to error; 
yet, if that part of the skin by which the sense is exercised is removed 
from its customary position, a false impression may be created in the 
mind. This is well illustrated by an experiment, which dates from 

21. The simplicity of touch ? What does it teach us ? 

22. Importance of the sense of touch to the development of the other senses ? 

23. Liability of touch to err ? Describe the illustration. 



THE SPECIAL SENSES. 229 

the time of Aristotle. If we cross the middle finger behind the fore- 
finger, and then roll a marble or some small object upon the tips of 
the fingers (see Fig. 54), the impression will be that two marbles 
are felt. If the fingers, thus transposed, be applied to the end of 
the tongue, two tongues will be felt. When 'the nose is accidentally 
destroyed, the surgeon sometimes performs an operation for the 
purpose of forming a new one, by transplanting a partially removed 




i 



Fig. 54. 



piece of the skin of the forehead upon the injured part ; then, if 
the new nose be touched or pinched, the feeling is referred to the 
forehead. This fact illustrates one important truth — that the nerves 
will re-unite after they have been cut and feeling will be restored ; 
if it were otherwise, a succession of slight cuts upon the fingers 
would seriously impair their tactile sensibility. 

24. The Delicacy of Touch. — Although the hand is the proper 
organ of this sense, yet it is exercised by various parts of the body, 
their degree of sensibility being proportional to the number of 
papillae they contain. The varying degrees of tactile delicacy of 
the different parts of the surface have been measured in an ingen- 
ious manner, by means of a pairof compasses, tipped with small 
pieces of cork. The two points of the compasses are touched at 
the same moment to the skin, the eyes being closed, and it is found 
that, in sensitive parts, the distance between the points may be 
quite slight, and yet each be plainly felt ; while, in less sensitive 
parts, the points of the compasses are felt as a single point, although 
they are separated one or two inches. 

24. The delicacy of touch ? Experiments with a pair of compasses ? 



230 THE SPECIAL SENSES. 

25. At the tips of the fingers, the distance between the points 
being one-twentieth of an .inch, a double impression is felt. The 
distance must be twice as great for the palm, four times as great 
for the lips, and, on the forehead, it must be twenty times greater. 
At the middle of the back, where the touch is least acute, the 
points must be separated more than two inches before they can be 
separately felt. Therefore, the sense of touch in the fingers is said 
to be fifty times more delicate than upon the posterior surface of 
the body. 

26. Exquisite delicacy of touch is attained by practice. This is 
shown in many of the lighter and more graceful employments of 
daily life. Without it, the skill of the painter, sculptor, and 
musician would be rude indeed. By training, also, the physician 
acquires the tactics eruditus, or discriminating touch; but among the 
blind, delicacy of touch- is most remarkable, and it there finds its 
highest value ; for its possession, in a measure, compensates for the 
loss of sight by enabling them to read, by means of raised letters, to 
work with certain tools, and even to play upon musical instruments. 
A person born without sight, and without hearing or voice, may, by 
the education of the touch, be rescued from apparent imbecility, and 
be taught not only to read and write, but even to perform household 
and other useful labors. 

27. Sensations of Temperature and Weight. — Each of these 
x. sensations has been described by the physiologists as a special 

sense, and they are rival candidates, so to speak, for the position and 
title of the sixth sense. In , the sensation of temperature, or the 
thermal sense, touch bears a part, but the two feelings appear to be 
distinct. In proof of this, we observe, firstly, that they are not 
alike intense in the same situations ; as, for example, the skin of 
the face and elbow, where the sense of touch is feeble, is very sensi- 
tive to impressions of heat and cold. Secondly, the ability to 
recognize temperature may be lost by paralysis, while the sensibility 
of touch remains unaffected. When the skin comes in contact with 
a very hot substance, the sensation felt is that of pain — not of 
touch. In like manner, a very cold substance causes pain, not the 

25. Further experiments and results? 

26. Exquisite delicacy of touch? The same among the blind? 

27. Rival candidates for the sixth sense ? Give the two reasons on the subject. 



THE SPECIAL SENSES. 231 

feeling of cold. So that a red-hot iron, and solid carbonic acid 
(the temperature of which is 108° below zero), feel alike; and 
each, if pressed slightly, will produce a blister. {Read Note 4.) 

28. The muscular sense, by some considered distinct from touch, 
gives rise to the sensations of weight, and other forms of external 
resistance. That this feeling exists, is shown by the following 
simple experiment : If the hand be placed flat upon a table, and a 
somewhat heavy weight be put into it, touch alone is exercised, and 
a feeling of pressure results ; but if the hand be raised, a certain 
amount of muscular effort must be put forth, and thus the sensation 
of weight is recognized. Through the muscular sense, precision of 
effort is rendered possible ; for by it we learn to adjust the force 
exerted to the weight of the object to be lifted, moved, or carried. 
Without it all our movements would necessarily become ill- 

4. Qualities Determined by the Sense of Touch. — " The eye, by 
the aid of certain signs, is often able to tell whether a body is hot — when, for 
instance, it is glowing or steaming — but a perception of warmth is not possessed 
by the eye. This is had by the skin alone, and it is of great importance to our 
preservation that this property is spread over the entire surface ; for it sur- 
rounds the body like a protecting wall against its worst enemy — cold — which, if 
not thus guarded against at all points, would speedily destroy life. We are 
warned, however, of the approach of the enemy by a common sensation of the 
skin, and an inward chill, which is only caused by a coolness of the skin. The 
skin, in like manner, protects the body against the approach of a hurtful de- 
gree of heat. Thus, you see, the skin has certain qualities of sensation. Just 
as the eye, in looking at a wafer perceives that it is both red and circular, 
distinguishing both the color and form of bodies, so the sensitive skin by con- 
tact with an object distinguishes the qualities of form, firmness, hardness, 
liquidity, pressure, and temperature. * * * Weber has discovered the in- 
teresting fact that warm bodies feel lighter than cold ones : if a cold coin be 
placed upon the forehead of some person, whose eyes are shut, and then upon 
the same spot two warm coins, the weight would seem to him the same, whilst 
he could distinguish correctly in the case of cold weights. * * * If we 
place the elbow in hot water, we experience heat only in the part immersed, 
not in the whole arm, although the nerve just under the skin runs throughout 
the arm and hand. What we feel is a dull sense of pain in the whole arm if 
the water is too hot. So, too, if the elbow is placed in ice- water the pain is 
just the same in the arm; proving that the nerve-trunk can feel neither 
warmth nor cold." — Bernstein's Five Senses of Man. 



28. The muscular sense ? State what is said to illustrate the subject. 



232 THE SPECIAL SENSES, 

regulated and spasmodic. In cases of disease, where the sensibility 
of the lower limbs is lost while power of motion remains, the patient 
is able to stand erect so long as he can see his limbs ; but just as 
soon as his eyes are closed, he begins to waver, and will fall unless 
supported. 

29. The Organ of Taste. — The tongue is the special organ of 
the sense of taste ; but the back part of the mouth always possesses' 
this faculty. The tongue is a muscular organ, the muscles composing 
it being so numerous and interwoven as to give it the freedom and 
variety of motion which it possesses. It can curve itself upward or 
downward ; it can extend or contract itself ; and, with its point, can 
sweep the cavity of the mouth, in all directions, in the search for 
scattered particles of food. 

30. The upper surface of the tongue is peculiar, being marked by 
the presence of innumerable jpapillce, some of which are of 
microscopic size, resembling those that abound in the fingers, and in 
other parts of the body that have the sense of touch. Others are 
much larger, and give to the tongue its roughness of feeling and 
appearance. Through the medium of these papillae, the tongue re- 
ceives impressions of touch and temperature, as well as taste : indeed, 
its extremity is fully as delicate, in respect to tactile sensations, as 
the tips of the fingers themselves. It can recognize the two points 
of the compasses when separated not more than one twenty-fourth 
of an inch ; the back of it is much less sensitive to touch, while at 
the same time it is more highly sensitive to impressions of taste. 

31. Each lateral half of the tongue resembles the other in 
structure, and each receives the same number of nerves — three. One 
of these regulates motion, the other two are nerves of special sense. 
One of the latter supplies the front half of the tongue, and is called 
the gustatory nerve. This is a branch of the great cranial nerve, 
called the " fifth pair," which ramifies in all parts of the face. The 
back of the tongue is endowed with the power of taste, through a 
nerve known as the glossopharyngeal, because it is distributed both 
to the tongue and throat. This difference in the nervous supply 
of the tongue becomes significant, when we learn, as we shaD 

29, The organ of taste ? The tongue ? Its powers of motion ? 

80. Peculiarities of the tongue? Uses of the papillae ? 

81. Resemblance in the parts of the tongue ? Powers and functions of the parts ? 



THE SPECIAL SENSES. 233 

presently, that each part of it perceives a different class of 
flavors. 

32. The Sense of Taste. — Taste is the special sense by means 
of which we discover the savors, or flavoring properties of the sub- 
stances which come in contact with the tongue. Mere contact with 
the surface of the tongue, however, is not sufficient, but contact 
with the extremities of the nerves of taste within the papillae is re- 
quired. In order that the substance to be tasted may penetrate the 
cells covering the nerves, it must either be liquid in form, or readily 
soluble in the watery secretion of the mouth — the saliva. The 
tongue must be moist also. If the substance be insoluble — as glass 
or sand — or the tongue dry, the sense of taste is not awakened. 
In sickness, when the tongue is heavily coated, the taste is very 
defective, or, as is frequently expressed, "nothing tastes aright." 

33. All portions of the tongue are not alike endowed with the 
sense of taste, that function being limited to the posterior third, and 
to the margin and tip of this organ. The soft palate, also, possesses 
the sense of taste ; henc3, an article that has an agreeable flavor 
may very properly be spoken of as palatable, as is often done. All 
parts of the tongue do not perceive equally well the same flavors. 
Thus, the front extremity and margin, which is the portion supplied 
by the " fifth pair " of nerves, perceives more acutely sweet and sour 
tastes ; but the base of the tongue, supplied by the glosso-pharyngeal 
nerve, is especially sensitive to salt and bitter substances. The 
nerve of the front part of the tongue, as before stated, is in active 
sympathy with those of the face, while the relations of the other 
nerve are chiefly with the throat and stomach ; so that when an 
intensely sour taste is perceived, the countenance is involuntarily 
distorted, and is said to wear an acid expression. On the other 
hand, a very bitter taste affects certain internal organs, and 
occasions a sensation of nausea, or sickness of the stomach. 
{Read Note$.) 

5. Flavors and the Sense of Taste.— "The cause and intimate 
nature of tastes are no better understood than those of odors. Flavors 



82. Taste? What are the requisites to taste ? 

33. Portions of the tongue endowed with taste ? Where else does the sense lodge ? What 
Is stated in respect to sweet and bitter flavors ? Reflex effects mentioned ? 



THE SPECIAL SENSES, 

34. Relations of Taste with other Senses. — Taste is not a 

simple sense. Certain other sensations, as those of touch, tempera- 
ture, smell, and pain, are blended and confused with it ; and certain 
so-called tastes are really sensations of another kind. Thus an 
astringent taste, like that of alum, is more properly an astringent 
feeling, and results from an impression made upon the nerves of 
touch, that ramify in the tongue. In like manner, the qualities 
known as smooth, oily, watery, and mealy tastes, are dependent 
upon these same nerves of touch. A burning or pungent taste is a 
sensation of pain, having its seat in the tongue and throat. A cool- 
ing taste, like that of mint, pertains to that modification of touch 
called the sense of temperature. 

35. Taste is largely dependent upon the sense of smell. A con- 
siderable number of substances, like vanilla, coffee, and garlic, 
which appear to possess a strong and distinct flavor, have in reality 
a powerful odor, but only a feeble taste. When the sense of smell 

elude analysis and defy classification, even that which divides them into 
agreeable and disagreeable, for the taste of individuals and of nations 
singularly differs in this respect. The Laplander and the Esquimaux 
drink great quantities of train-oil, which for them is a greatly-esteemed 
article of food, and is most admirably adapted to the exigencies of a Polar 
climate ; the Abyssinians eat raw flesh, and find its flavor excellent, while 
the inhabitant of the "West partakes of it with the greatest repugnance 
and only as a medicine. Oysters, which are so generally esteemed in 
our country, are to some persons disagreeable and nauseous ; and truffles, 
the delight of the gourmand, are rejected by the uninitiated on account 
of their flavor and their perfume. It is the same with almost all alimentary 
substances ; they are eagerly sought after by some, and despised or 
abhorred by others. Let us remember the proverb ' de gustibus non 
disputandum,' and not dispute in regard to tastes; each is suited to its 
own country, and goodly numbers acclimatize themselves, to the great 
advantage of peoples among whom at first they seem exceedingly strange. 
Man should control his taste, and habituate it to all wholesome aliment ; 
this neither excludes choice, nor blunts the delicacy of the sense ; and 
while we resist its seductions, we should give timely heed to its instincts 
and its counsels, for they are often invaluable." — The Wonders of the Human 
Body. 



34. What is stated of the relations of taste to other senses? 

35. Its dependence on smell t on sight ? 



THE SPECIAL SENSES. 235 

is interfered with by holding the nose, it becomes difficult to dis- 
tinguish between substances of this class. The same effect is fre- 
quently observed when smell is blunted during an ordinary cold in 
the head. Sight also contributes to taste. With the eyes closed, 
food appears comparatively insipid ; and a person smoking tobacco 
in the dark is unable to determine by the taste whether his cigar is 
lighted or not. Accordingly, it is not a bad plan to close the nose 
and shut the eyes when about to swallow some disagreeable medi- 
cine. 

36. Influence of Education on the Taste. — The chief use of 
the sense of taste appears to be to act as a guide in the selection of 
proper food. Hence its organs are properly placed at the entrance 
of the digestive canal. As a general rule, those articles which 
gratify the taste are wholesome; while the opposite is true of those 
which impress it disagreeably. This statement is more exact in 
reference to the early than to the later years of life, when, by reason 
of improper indulgence, the sense of taste has become dulled or per- 
verted. The desires of a child are simple ; he is fully satisfied with 
plain and wholesome articles of diet, and must usually " learn to 
like " those which have a strongly marked flavor. Accordingly, it 
is far easier at this age to encourage the preference for plain food, 
and thus establish healthful habits, than later in life to uproot 
habits of indulgence in stimulating substances, after their ill effects 
begin to manifest themselves. 

37. The tastes of men present the most singular diversities, 
partly the result of necessity and partly of habit or education. 
The Esquimaux like the rank smell of whale-oil, which is a kind of 
food admirably suited to the requirements of their icy climate ; and 
travelers who go from our climate to theirs are not slow to develop 
a liking for the same articles that the natives themselves enjoy. 
The sense of taste is rendered very acute by education, as is shown 
in an especial manner by those who become professional " tasters * 
of tea and wine. 

38. The Sense of Smell— the Nasal Cavities. — The sense of 



36. The chief use of the sense of taste ? The position of its organs ? The rule as regards 
wholesome and unwholesome food ? Remarks respecting the rule ? 

37. Diversity in tastes of men ? How shown ? The education of the sense of taste ? 

38. Location of the sense of smell ? The nose ? " Roof of the mouth 1" 



THE SPECIAL SENSES. 

smell is located in the delicate mucous membrane which lines the 
interior of the nose. That prominent feature of the face, the nose, 
which is merely the front boundary of the true nasal organ, is com* 
posed partly of bone and partly of cartilage. The upper part of it 
is united with the skull by means of a few small bones, to which 
circumstance is due its permanence of shape. The lower portion, 
or tip of the nose, contains several thin pieces of cartilage, which 
render it flexible and better able to resist the effects of blows and 
pressure. Behind the nose we find quite a spacious chamber, 
separated from the mouth by the hard palate, forming the " roof 
of the mouth," and also by the soft palate (see Fig. 55) ; and 
divided into two cavities by a central partition running from before 
backward. 

39. These nasal cavities, constituting the true beginning of the 
air-passages, extend from the nose backward to the upper opening 
of the throat, and rise as high as the junction of the nose with the 
forehead. The inner wall of each cavity is straight and smooth ; 
but from the outer wall there jut into each cavity three small scroll- 
like bones. The structure of these bones is very light, and hence 
they have been called the " spongy " bones of the nose. In this 
manner, while the extent of surface is greatly increased by the for- 
mation of these winding passages, the cavities are rendered extremely 
narrow ; so much so, in fact, that a moderate swelling of the mucous 
membrane which lines them, as from a cold, is sufficient to obstruct 
the passage of air through them. 

40. The Nerve of Smell. — The internal surface of the nasal 
passages is covered by a delicate and sensitive mucous membrane. 
Its surface is quite extensive, following as it does all the inequali- 
ties produced by the curved spongy bones of the nose. Only the 
upper portion of it is the seat of smell, since that part alone re- 
ceives branches from the "first pair" of cranial nerves, or the 
olfactory nerve, which is the special nerve of smell (see Fig. 55). 
In Fig. 55 is shown the distribution of this nerve, in the form of 
an intricate network upon the two upper spongy bones. The nerve 
itself (1) does not issue from the skull, but rests upon a thin bone 

89. Cavities of the nose ? Obstruction of the passage of air through them ? 
40. The special nerve of smell ? Its location f 



THE SPECIAL SENSES. 



237 




Fig. 55.— Section of the Right Nasal Cavity. 



which, separates it from the cavity of the nose ; and the branches 
which proceed from it pass through this bone by means of numer- 
ous small openings. The engraving represents the outer surface of 
the right nasal cavity ; the three wave-like inequalities, upon which 
the nervous network is spread out, are due to the spongy bones. 
The left cavity is supplied in the same manner. 

41. The nerves which 
ramify over the lower part 
of the membrane, and which 
endow it with sensibility to 
touch and pain, are branches 
of the " fifth pair" of nerves. 
An irritation applied to the 
parts where this nerve is 
distributed occasions sneez- 
ing — that is, a spasmodic 
contraction of the dia- 
phragm, the object of which 
is the expulsion of the irritating cause. The manner in which the 
olfactory nerve-fibres terminate is peculiar. Unlike the extremities 
of other nerves, which are enclosed by a greater or less thickness of 
tissue, these come directly to the surface of the mucous membrane, 
and thus are in very close contact with the odorous particles that 
are carried along by the respired air. The surface is at all times 
kept in a moist condition by an abundant flow of nasal mucus ; 
otherwise it would become dry, hard, and insensitive from the con- 
tinual passage of air to and fro in breathing. Birds, which respire, 
more actively than men, have a special gland for secreting a lubri- 
cating fluid, located in the air-passages of the head. 

42. The Uses of the Sense of Smell.— Smell is the special 
sense which enables us to appreciate odors. Touch, as we have 
seen, is largely concerned with solid bodies, and taste with fluids, 
or with solids in solution. Smell, on the other hand, is designed 
to afford us information in reference to substances in a volatile or 
gaseous form. Invisible particles issue from odorous bodies and 

41. Branches of the " fifth pair" of nerves? Nasal mucus? Birds? 

42. Smell? Touch? Taste? Design of smell ? Invisible and gaseous particles? The 
extreme fineness of the particles ? Musk ? In other cases ? 



238 THE SPECIAL SENSES. 

are brought by the respired air in contact with the terminal fila- 
ments of the olfactory nerve, upon which an agreeable or disagree- 
able impression is produced. The fineness of the particles that 
constitute odors is often so extreme that they elude all attempts 
to measure or weigh them. A piece of musk, for instance, may be 
kept for several years, constantly emitting perfume without any 
appreciable loss of weight. In other cases, a loss of substance is 
perceptible, as in the essential oils, which enter into the composi- 
tion of the ordinary perfumes. 

43. Smell, like taste, aids us in the choice of proper food, lead- 
ing us to reject such articles as have a rank or putrid odor, and 
which are, as a Tule, unfit to be eaten. The highest usefulness of 
this sense, however, consists in the protection it affords to the 
organs of respiration. Stationed at the gateways of the air-passages, 
it examines the current of air as it enters, and warns us of the 
presence of noxious gases, and of other and generally invisible 
enemies to health. Not all dangerous vapors are offensive, but al- 
most all offensive vapors are unfit to be breathed. A number of 
small stiff hairs grow from the margin of the nostrils to prevent 
the entrance of dust and.other atmospheric impurities, which would 
be alike injurious to the olfactory mucous membrane and to the 
lungs. The benevolent design of the Maker of our bodies may be 
observed in all parts of their mechanism • but, probably, in none is 
it more clearly displayed than in connection with the sense of smell. 
{Read Note 6.) 

6. The Protective Function of the Sense of Smell. — "Smell 
seems to be regarded as an endowment bestowed simply for pleasure, serving 
to promote no important or vital end. That its main use is to signal danger 
to internal parts is not duly appreciated. The detection of an offensive odor 
is thought to be the only bad thing about it, and which, to those habituated 
to it, is of no subsequent importance. Men even pride themselves, on becom- 
ing accustomed to offensive odors, and quite enjoy the sight of one whose nerve 
of smell is not benumbed like their own. Instead of seeking to blunt the 
sensibilities of this nerve, it should be a study to improve it, as the most deli- 
cate and available test of air impurity — far superior, under ordinary circum- 
stances, to the tests of science. In this way, all ordinary atmospheric impu- 
rities may be quickly detected ; and it is truly remarkable how, by a little 
attention, this sense can be so improved as to detect instantly even slight im- 
48. Ai« given by smell t The highest use of the sense ? Explain the manner. . 



THE SPECIAL SENSES. 239 

44. The sense of smell is developed in a remarkable degree in 
certain of the inferior animals, and is especially acute in reference 
to the peculiar odors that characterize the different animals. The 
lion and other carnivorous beasts scent their prey from a great dis- 
tance ; and the fox-hound is able to track the fox through thickets 
and over open country for many miles ; while the timid, helpless 
herbivora, such as the deer and sheep, find in the sense of smell a 
means of protection against their natural enemies, of whose approach 
they are in this manner warned. By training this sense in the dog, 
and making it subservient to his use, man is able to hunt with suc- 
cess certain shy and very fleet animals, which otherwise he could 
but seldom approach. Among men, individuals differ greatly in 
respect to the development of this sense ; and especially in certain 
savage tribes it is found to be extremely delicate. Humboldt states 
that the natives of Peru can by it distinguish in the dark between 
persons of different races. {Read Note 7. ) 

purities to which it had before been insensible. In many houses, by the total 
neglect of this sense, there is an ever-present family odor, produced by some 
special kind of household impurity, and of which the inmates do not seem to 
be aware. To those accustomed to pure air, house odors are always perceptible 
and disagreeable. This ought to be accepted as sufficient evidence of their 
unhealthful tendencies ; not perhaps of an instant or violent sort, yet enough so 
to give rise to many sensations of slight discomfort, and producing, when long 
continued, a state of the body very favorable to the beginning and growth of 
virulent diseases." — Black's Ten Laws of Health. 

7. The Effects of Certain Odors. — " I have not seen it anywhere laid 
down as a general rule, but I believe it might be affirmed, that we are intended 
to be impressed only sparingly and transiently by odor. There is a provision 
for this in the fact that all odors are vapors or gases, or otherwise volatile sub- 
stances ; so that they touch but the inside of the nostril, and then pass away. 

' ' In conformity with this fleeting character of odorous bodies, it is a law in 
reference to ourselves, to which, as far as I know, there is no exception, that 
there is not any substance having a powerful smell of which it is safe to take 
much internally. The most familiar poisonous vegetables, such as the poppy, 
hemlock, henbane, monk's-hood, and the plants containing prussic acid, have 
all a strong and peculiar smell. Nitric, muriatic, acetic, and other corrosive 
acids, have characteristic potent odors, and all are poisons. Even bodies with 
agreeable odors, like oil of roses, or cinnamon, or lavender, are wholesome only 
in very small quantities, and, when the odor is repulsive, only in the smallest 



44. Sense of smell in the inferior animals ? How, and in what cases, illustrated ? 




240 THE SPECIAL SENSES. 

45. The Sense of Sight.— Sight, or vision, is the special sense 
y means of which we appreciate the color, form, size, distance, and 

other physical properties of the objects of external nature. Primarily, 
this sense furnishes us with information concerning the different 
shades of color and the different degrees of brightness : these are 
the simple sensations of sight, such as the yellowness and glitter of 
a gold coin. In addition to these, there are composite visual sen- 
sations, produced by the joint action of the other senses and by the 
use of the memory and judgment ; such as, in the case of the coin, 
its roundness, solidity, size, its distance and direction from us. So 
that many of our sensations, commonly considered as due to sight, 
are in reality the results of intellectual processes which take place 
instantaneously and unconsciously. 

46. This faculty not only is valuable in the practical e very-day 
affairs of life, but it contributes so largely to the culture of the 
intellect and to our higher forms of pleasure, that some writers are 
disposed to rate it as the first and most valuable of the senses. 
Others, however, maintain that the sense of hearing does not yield 
in importance to that of sight ; and they cite in support of their 
position the fact that the blind are commonly cheerful and gay, 
while the deaf are inclined to be morose and melancholy. In re- 
spect to the relative capacity for receiving education in the deaf and 
blind, it is found that the former learn more quickly, but their at- 
tainments are not profound ; while the blind acquire more slowly, 
but are able to study more thoroughly. 

47. Light — The Optic Nerve. — Unlike the senses previously 
considered — touch, taste, and smell — sight does not bring us into 

quantities. So far as health is concerned, the nostril should be but sparingly 
gratified with pleasing odors or distressed by ungrateful ones. No greater 
mistake can be made in sick-rooms than dealing largely in aromatic vinegar, 
eau de cologne, lavender water, and other perfumes. This hiding of one odor 
by another is like trying to put away the taste of bitter aloes by that of Epsom 
salts. Physical comfort is best secured by rarely permitting an infraction of 
the rule that the condition of health is no odor at alL" — Wilswa on the 
Five Gateways of Knowledge. 



45. What is sight? What information dues it furnish? Composite visual sensations! 

46. Comparison between sight and hearing ? Relative capacity of deaf and blind. 

47. Sight, unlike the other senses ? In the case of the stars 1 



THE SPECIAL SENSES. 241 

immediate contact with the bodies that are examined ; but, by it, 
we perceive the existence and qualities of objects that are at a 
greater or less distance from us. In the case of the stars, the dis- 
tance is incalculable, while the book we read is removed but a few 
inches. Light is the agent which gives to this sense its wide range. 
The nature of this mysterious force is not known, and it is not here 
to be discussed, since its study belongs more properly to the prov- 
ince of natural philosophy. 

48. It is sufficient, in this connection, to state that the theory 
of light now generally accepted, and which best explains the facts 
of optics, is that known as the undulatory theory. This theory 
supposes that there exists an intangible, elastic medium, which fills 
all space, and penetrates all transparent substances, and which is 
thrown into exceedingly rapid undulations or waves, by the sun 
and every other luminous body — the undulations being propagated 
with extreme rapidity, and moving not less than 186,000 miles in 
a second. 

49. These waves are thought to produce in the eye the sensation 
of light, in the same manner as the sonorous vibrations of the air 
produce in the ear the sensation of sound. That part of the eye 
which is sensitive to these waves is the expansion of the optic 
nerve. It is sensitive to no other impression than that of light, and 
it is the only nerve which is acted upon by this agent. The optic 
nerve, also called the "second pair" of cranial nerves, is the means 
of communication between the eye and the brain. 

50. The two nerves constituting the pair arise from ganglia 
lying at the base of the cerebrum — one of them on each side — from 
which points they advance to the eyes, being united together in the v 
middle of their course in the form of the letter X (Fig. 51-2) 
By this union the two eyes are enabled to act harmoniously, and in 
some respects to serve as a double organ. By reason of this same 
intimate nervous communication, when serious disease affects one 
eye, the fellow-eye is extremely liable to become the seat of sym- 
pathetic inflammation ; and this, if neglected, almost certainly re- 
sults in hopeless blindness. 

48. The undulatory theory of light? What does the theory suppose? 

49. The sensation of light ? Optic nerve? 

50. The two nerves constituting the pair of nerves? 

11 



242 THE SPECIAL SENSES. 

5!. The Organ of Sight— The Eye.— The proximity of the 
eye to the brain, and the important part it performs in giving ex- 
pression to the emotions, have given it the name of " the window 
of the soul." The exceeding beauty of its external parts, and the 
high value of its function, have long made this organ the subject of 
enthusiastic study. It is chiefly within the last twenty years, how- 
ever, that this study has been successful and fruitful of practical 
results. Several ingenious instruments have been invented for the 
examination of the eye in health and disease, and new operations 
have been devised for the relief of blindness and of impaired vision. 
As a result, it is now a well-marked fact that, in civilized lands, the 
number of those who suffer from loss of sight is proportionally much 
less than in countries where science is less known and cultivated. 

52. The most obvious fact in respect to the apparatus of sight is 
that there are two eyes, which may either act together as one, and 
be fixed upon one object, or one eye may be used independently of 
the other. In consequence of this arrangement, the loss of one eye 
does not necessitate blindness, and, in fact, it not infrequently 
happens that the sight of one eye may be long impaired or lost be- 
fore the fact is discovered. 'We next notice that it is placed at the 
most elevated part of the body, in front, and near the brain. It 
also commands a wide range of view, being itself moved with great 
rapidity, and being further aided by the free motion of the head 
and neck. The organ of vision consists essentially of two parts : 
the optical instrument itself — the eyeball — and its enveloping parts, 
or the case in which the instrument is kept free from harm. The 
latter, which are external, and which we shall first consider, are 
chiefly the orbits, the eyelids, and the apparatus for the tears. 

53. The Orbits. — The eyeball, which is a delicate organ, is 
well defended against external injury within the orbits or bony 
sockets of the head. These are deep conical hollows, bounded in 
part by the tones of the skull, and in part by those of the nose and 
cheek. The orbit juts out beyond the most exposed portion of the 



51. Why is the eye called the " window of the soul ?** Why the subject of enthusiastic 
study ? 

52. The most obvious fact? The consequence? The next thing noticed? Its range 
of view ? Of what does the organ of vision consist ? 

53. The protection of the eyeball against injury ? The overhanging brow? The opening 
for the optic nerve ? 



THE SPECIAL SENSES. 243 

eyeball, as may be seen by laying a book over the eye, when it will 
be found that no part of the eyeball, unless it be very prominent, 
will be touched by the book ; so that the only direction in which 
an injury is liable to be received is immediately in front of the eye. 
The overhanging brow is itself covered by a layer of thick skin, 
studded with short, stout hairs, which are so bent as to prevent 
the perspiration from running into the eye and obscuring vision. 
Through a hole in the bottom of the orbit, the nerve of sight passes 
outward from the brain. The orbit also contains a considerable 
amount of a fatty tissue, upon which, as upon an elastic cushion, 
the eye rests. 

54. The Eyelids. — The eyelids are two movable curtains, or 
folds, which, when shut, cover the front part of the orbit, and hide 

the eye from view. The upper 
lid is the larger, has a curved 
margin, and moves freely, whilb 
the lower lid is comparatively 
short and straight, and has but 
a slight degree of motion (Fig. 
2 56). Skin covers the exterior 
of the lids, while a fine mucous 
membrane lines their inner sur- 
/ / face, and is likewise spread out 

(N2ia?Si^.f R0NT VlEW ° F RlGHT EYE * 0Ver tlie eiltire fr0nt ° f tlie 

«iVwif Lachr y ma J> or tear s land > lying te - eyeball. This membrane, which 

neath the upper eyelid. J ' 

2. Tiie Nasal Duet is show by the dotted line. i s called the conjunctiva, is highly 

The * marks tne orifice in the lower lid. J > o «/ 

The central black spot is the pupil; sur- sensitive, and thus plays an iru- 

roundmg it is the iris; and the triangular x J 

white spaces are the visible portion of the portant part in protecting the 

eye against the lodgment of sand, 
ashes, chaff, and other foreign particles that are blown about in the 
air. This sensitive membrane will not endure the presence of 
these particles. If any find access, it causes a constant winking, 
a flow of tears, and other signs of irritation, until it is removed. 
{Read Note 8.) 

8. How to Remove Foreign Bodies from the Eye. — "Laj 
your finger on the cheek, and draw the lower lid gently down, while the 

54. What are the eyelids? The upper lid ? The lower one? Tlie mucous membrane of 
the eye? 




244 THE SPECIAL SENSES. 

55. The long, silky eyelashes, which garnish the edges of the 
lids, act like a sieve to preyent the entry of dust and other irri- 
tants ; and together with the lids, they regulate the amount of light 
which is permitted to enter the eye, so that it is shielded from a 
sudden flood or glare of light. The little points seen in the figure 
just within the line of the lashes, especially on the lower lid, repre- 
sent the mouths of numerous little sebaceous glands (Fig. 57, d, d), 
such as are always found in the neighborhood of hairs. These 
glands supply a thick, oily material which greases the edges of the 
lids and prevents their adhering together, and likewise prevents the 
overflow of the tears upon the cheek. 

56. The Lachrymal Fluid, op the Tears. — Just within the 
outer part of the bony arch of the brow, where the bone may be 
felt to be sharper than in other positions, is lodged a little organ 
called the lachrymal gland, the situation of which is indicated in 

person looks as much upward as possible, and we shall see about the whole 
extent of the lower portion of the conjunctiva, and thus, if any foreign sub- 
stance is there, it will be readily detected, and easily wiped away with a folded 
soft rag or handkerchief. Both lids have a piece of cartilage in them to stiffen 
them, like pasteboard, and keep them fitting close to the eyeball. The upper 
portion of this conjunctival sac can only be seen by turning over the upper 
lid. The way to do this is to let the person look down with the eyes closed. 
Taking hold of the lashes with one hand, and applying a pencil, or some small, 
round, smooth object, over the lid above the globe, we lift the lashes out and 
up, warning the person to still keep looking down. The lid will suddenly 
turn over with a little spring from the bending of the cartilage. In this way 
nearly the whole of the conjunctival sac will be exposed, and any foreign 
body wiped away, as above described. But suppose no friend or oculist is by 
us to do this. The next best thing is to take hold of the lashes of the upper 
lid, and draw it forward and downward over the lower one, blowing the nose 
violently with the other hand at the same time. 

" If the foreign substance is on the cornea, take a strip of paper not stiffer 
than ordinary writing-paper, about a quarter of an inch wide, and roll it up as 
if you were going to make a candle-lighter. Look at the lo\ *er end, and you 
will see it comes to a point. "With this point now you may safely attempt to 
remove any foreign substance from the corn"*. The tears which will flow 
soften the paper, and prevent injury to the delicate covering membrane of the 
cornea." — Dr. B. Jay Jeffries. 

55. The eyelashes ? The little points within the line of the lashes ? Of what use are 
these glands ? 

66. The location of the lachrymal gland ? The use of the gland? 



THE SPECIAL SENSES. 245 

Fig. 56, 1. This is the gland whence flows the watery secretion, 
commonly called the tears, which is designed to perform an exceed- 
ingly important duty in lubricating the lids, and in keeping the ex- 
posed surface of the eyeball moist and transparent. For, without 
this or some similar liquid, the front of the eye would speedily 
become dry and lustreless, like that of a fish which has been re* 
moved from the water ; the simple exposure of the eye to the aii 
would then suffice to destroy vision. 

57. This secretion of the tears takes place at all times, during 
the night as well as the day ; but it is seldom noticed, unless when 
under the influence of some strong mental emotion — whether of sor- 
row or happiness — it is poured forth in excess, so as to overflow the 
lids. Strong light or a rapid breeze will, among many other causes, 
excite the flow of the tears. That portion of this secretion which 
is not used in moistening the eye is carried off into the nose by a 
canal situated near the inner angle of the eye, called the nasal duct. 
This duct is shown in Fig. 56, 2, and is connected with each lid by 
delicate tubes, which are indicated by dotted lines in the figure ; 
the asterisk marks the little opening in the lower lid, by which the 
tears enter the nasal duct. By gently turning the inner part of that 
lid downward, and looking in a mirror, this small "lachrymal 
point " may be seen in your own eye. In old people, these points 
become turned outward, and do not conduct the tears to the nasal 
cavity, thus causing an overflow of tears upon the face. 

58. Thus we observe that the gland which forms the tears is 
placed at the outer part of the eye, while their means of exit is at 
the inner angle of the eye ; which fact renders it necessary that this 
watery fluid shall pass over the surface of the eyeball before it can 
escape. This arrangement cannot be accidental, but evinces design, 
as it thus secures the perfect lubrication of the surface of the eye, 
and cleanses it from the smaller particles of dust which may enter 
it, in spite of the vigilance of the lids and lashes. The act of 
winking, which is generally unconsciously performed, and which 
takes place six or more times in a minute, assists this passage of the 



57. When does the secretion of the tears occur? The secretion not used for the eye? 
Location of the nasal duct? Its use? The overflow of tears in old people? 

58. The watery fluid passing over the eyeball? Design of the arrangement ? Winking? 



246 



THE SPECIAL SENSES. 



tears across the eye, and is especially frequent when the secretion is 
most abundant. 

59. The Eyeball. — The eyeball, or globe of the eye, upon which 
sight depends, is, as the name indicates, spherical in shape. It is 
not a perfect sphere, since the front part projects somewhat beyond 
the rest, and at the posterior part the optic nerve (Fig. 57, n) is 
united to it, resembling the junction of the stem with the fruit. In 




Fig. 57.— Vertical Section of The Eye. (Enlarged.) 



C, The 

A, The 
I, The 
P, The 
L, The 
H, The 

B, The 
V, The 
S, The 



Cornea. 

Aqueous Humor. 

Iris. 

Pupil. 

Crystalline Lens. 

Ligament of the Lens. 

Ciliary Process. 

Cavity containing the Vitreous Humor. 

Sclerotic. 



Ch, The Choroid. 

R, The Retina. 

N, The Optic Nerve. 

DD, The Eyelids. 

X, The Levator Muscle of the Upper 

Lid. 
Y, The Upper Straight Muscle of the 

Eye. 
Z, The Lower Straight Muscle. 



its long diameter — that is, from side to side, it measures a little 
more than an inch ; in other directions it is rather less than an inch. 
In structure the ball of the eye is firm, and its tense round contour 
may in part be felt by pressing the fingers over the closed lids. 

60. The eyeball is composed chiefly of three internal, transparent 
media, called humors, and three investing coats, or tunics. The 



59. Describe the shape of the eyeball. Its structure. 

60. Of what is the eyeball composed ? State how. 



THE SPECIAL SENSES. 247 

former are the aqueous humor, Fig. 57, A* the crystalline lens l, and 
the vitreous humor v. Of these the lens alone is solid. The three 
coats of the eyeball are called the sclerotic s, the choroid Ch, and 
the retina r. This arrangement exists in respect tc fh sixths of 
the globe of the eye, but in the anterior one-sixth, these coats are 
replaced by the cornea c, which is thin and transparent, so that the 
rays of light pass freely through it, as through a clear window- 
pane. 

61. In shape, the cornea is circular and prominent, resembling a 
miniature watch-glass, about -^ of an inch thick. In structure, 
it resembles horn (as the name signifies), or the nail of the finger, 
and is destitute of blood-vessels. The sclerotic (from scleros, hard) 
is composed of dense, white fibrous tissue, and gives to the eyeball 
its firmness of figure and its white color ; in front, it constitutes the 
part commonly called "the white of the eye." It is one of the 
strongest tissues in the body. It possesses very few vessels, and 
is not very sensitive. It affords protection to the extremely delicate 
interior parts of the eye, and the little muscles which effect its 
movements are inserted into the sclerotic a short distance behind 
the cornea (see Fig. 57, y, z). It is perforated posteriorly to admit 
the optic nerve. 

62. The choroid is the second or middle coat of the eyeball, and 
lies closely attached to the inner surface of the sclerotic. Unlike 
the latter, its structure is soft and tender ; it is dark in color, and 
possesses a great abundance of blood-vessels. Its dark color is due 
to a layer of dark brown or chocolate-colored cells spread out over 
its inner surface. This dark layer serves to absorb the rays of 
light after they have traversed the transparent structures in front of 
it. If the rays were reflected from side to side within the eye, 
instead of being thus absorbed, confused vision would result from the 
multitude of images which would be impressed upon the optic nerve. 

63. This mechanism has been unconsciously imitated by the 
opticians, who, when they make a microscope or telescope, take care 
that the interior of its tube shall be coated with a thick layer of 



61. The shape of the cornea? Its structure? The "white of the eye?" 

62. The second or middle coat of the eyeball? Its dark color? 

63. Similar mechanism in microscopes'? The albinos? White rabbits ? 



248 



THE SPECIAL SENSES. 



black paint or lamp-black ; for without it, a clear delineation of the 
object to be viewed is impossible. The Albinos, in whom these dark 
cells of the choroid are wanting, have imperfect vision, especially in 
the daytime and in strong lights. The dark cells are also wanting in 
white rabbits, and other animals that have red or pink eyes ; their 
vision appears to be imperfect in the presence of a brightlight. 
\f 64. The Iris. — Continuous with the choroid, in the front part of 
y\ the globe of the eye, is a thin, circular curtain, which occasions the 
brown, blue, or gray color of the eye in different individuals. On 
account of the varieties of its color, this membrane has received the 

name 7m, which is the Greek 
word for "rainbow" (see Fig. 
57, i). A front view of it is 
shown in Fig. 56. The iris 
is pierced in its centre by a 
round opening, called the 
pupil (p), which is constantly 
varying in size. In olden 
times it was spoken of as the 
" apple of the eye." The 
hinder surface of the iris, 
except in Albinos, has a 
layer of dark coloring mattei 
resembling that of the cho- 
roid. The iris is a musculai 
organ, and contains two dis- 
tinct sets of fibres, one of which is circular, while the other radiates 
outward from the pupil. Their action regulates the size of the 
pupil ; for when the circular set acts, the opening contracts. Their 
action is involuntary, and depends on the reflex system of nerves, 
which causes the contraction of the pupil when a strong light falls 
upon the eye, and its expansion when the illumination is feeble. The 
suspensory ligament holds the crystalline lens in its place. Fig. 58. 
65. The iris, accordingly, serves a very useful purpose in regulat- 
ing the admission of light to the eye (see Fig. 58). It, however, 

64 What is the iris ? Its construction ? How is the size of the pupil regulated ? 
65. The admission of light to the eye ? The action of the iris under different crrcum- 
etances? The lustre of the eye, how affected in youth and old age ? 




Fig. 58. — Front Section of its Eyeball, 
viewed from behind, and showing sus- 
PENSORY Ligament, Iris, and Pupil. 



THE SPECIAL SENSES. 249 

does not act instantaneously; and hence, when we pass quickly 
from a dark room into the bright sunlight, the vision is at first con- 
fused by the glare of light, but as soon as the pupil contracts, th& 
ability to see becomes perfect. On the other hand, when we enter 
a dark apartment, such as a cellar, for a short time we can see 
nothing clearly ; but as soon as the pupil expands and admits more 
light, we are enabled to distinguish the surrounding objects. Ani- 
mals of the cat species, and others which prowl around after night- 
fall, are enabled to see in the dark by having the iris very dilatable. 
The size of the pupil affects the lustre of the eye. When it is 
large, as it usually is during youth, the eye appears clear and 
brilliant ; while in old age the pupil is small and the eye is dull. The 
brilliancy of the eye is in part, at least, dependent upon the reflec- 
tion of light from the front surface of the crystalline lens. 

66. Certain poisonous vegetables have the property of causing the 
pupil to dilate, and have been used in small doses to increase the 
beauty of the eye. One of these drugs has been so largely used by 
the ladies for this purpose, that it has received the name belladonna, 
from the Italian words meaning " beautiful lady." This hazardous 
practice has resulted more than once in the death of the person 
desiring thus to increase her personal attraction. The common 
English name for belladonna is " deadly nightshade." (In the dia- 
gram on page 257 the shape and relations of the iris are more accu- 
rately shown than in the figure referred to above.) 

67. The Retina constitutes the third and inner coat of the globe 
of the eye. This, the important part of the eye that is sensitive to 
light, is a kind of nervous membrane, formed by the expansion of 
the optic nerve. Its texture is soft, smooth, and very thin ; it is 
translucent and of an opaline, or grayish- white color. It is sensi- 
tive to light alone; and if any form of mechanical irritation be 
applied to it, the sensations of touch and pain are not experienced, 
but flashes of fire, sparks, and other luminous appearances are per. 
ceived. Thus an electric shock given to the eyeball occasions a 
flash of light ; and a sudden fall, or a blow upon the eye, is often 
apparently accompanied by the vision of " stars." 

66. Means used to increase the beauty of the eye ? The injurious consequences ? 

67. What part does the retina constitute ? How formed? Its texture? Color? Sensi- 
tiveness ? 



250 



THE SPECIAL SENSES. 



68. These phenomena are due to what is termed the "specific 
energy " of the optic nerve, which nerve, in common with the other 
nerves of the special sense, obeys a general law of nature, which re- 
quires that, whenever one of these nerves is stimulated, it shall 
respond with the sensation peculiar to itself. These flashes of 
retinal light have no power to illuminate external objects, although 
the opposite of this statement has been maintained. On the occasion 
of a remarkable trial in Germany, it was claimed by a person who 
had been severely assaulted on a very dark night, that the flashes of 
light caused by repeated blows upon the head enabled him to see 
with sufficient distinctness to recognize his assailant. But the 
evidence of scientific men entirely refuted this claim, by pro- 
nouncing that the eye, under the circumstances named, was 
incapacitated for vision. Too intense light occasions a feeling of 
pain, but it is of a peculiar kind, and is termed " dazzling." 

69. All parts of the retina are not equally sensitive, and sin- 
gularly enough, the point of entry of the nerve of sight in the back 
part of the eyeball is entirely insensible to light, and is called the 
" blind spot." The existence of this point may be proved by a 
simple experiment. Hold the accompanying figure, on page 250, 
directly in front of and parallel with the eyes. Close the left eye, 




Fig. 59. 

and fix the sight steadily on the left-hand circle ; then, by gradually 
varying the distance of the figure from the eye, at a certain distance 
(about six inches), the right-hand circle will disappear, but nearer or 
further than that, it will be plainly seen. The other eye may be 
also tried, with a similar result : if the gaze be directed to the right- 
hand circle, the left one will seem to disappear. The experiment 



68. Specific energy of the optic nerve ? Trial in Germany? 

69. Sensitiveness of all parts of the retina? Experiment to prove the existence of the 
blind spot?" 



THE SPECIAL SENSES. 251 

may be repeated by using two black buttons on the marble top of a 
bureau, or on some other white surface. The blind spot does not 
practically interfere with vision, since the eye is seldom fixed 
immovably on an object, and the insensitive parts of the two eyes 
can never be directed upon the same object at the same time. 

70. Impressions made upon the retina are not at once lost, but 
continue a measurable length of time, and then gradually fade away. 
Thus, a bright light or color, gazed at intently, cannot be immedi 
ately dismissed from sight by closing or turning away the eyes. A 
stick lighted at one end, if whirled around rapidly in the dark, pre- 
sents the appearance of an unbroken luminous ring ; and the spokes 
of a rapidly revolving carriage-wheel seem to be merged into a plane 
surface. If an object move too rapidly to produce this sort of 
lasting impression, it is invisible, as in the case of a cannon-ball 
passing through the air in front of us. 

71. If a card, painted with two primary colors — as red and yellow 
— be made to rotate swiftly, the eye perceives neither of them dis- 
tinctly ; but the card appears painted with their secondary color — 
orange. The average duration of retinal images is estimated at one- 
eighth of a second ; and it is because they thus endure, that the act 
of winking, which takes place so frequently, but so quickly, is not 
noticed and does not interrupt the vision. The retina is easily 
fatigued or deprived of its sensibility. After looking steadfastly 
at a bright light, or at a white object on a black ground, a dark spot, 
corresponding in shape to the bright object, presents itself in 
whatever direction we look. This spot passes away as the retina 
resumes its activity. 

72. If a white color be gazed at intently, and the eyes theii be 
turned to a white surface, a spot will appear ; but its color will be 
the complement of that of the object. Fix the eye upon a red 
wafer upon a white ground, and on removing the wafer a greenish 
spot of the same shape takes its place. This result happens because 
a certain portion of the retina has exhausted its power to perceive 
the red ray, and perceives only its complementary ray, which is 

70. Duration of impressions upon the retina? How illustrated? 

71. What further illustration? Winking, why it is not noticed? Ease with which the 
utina is fatigued or deprived of sensibility ? How shown ? 

72. How further shown? How is the result accounted for? " Color-blindness?" 



252 THE SPECIAL SENSES. 

green. The color thus substituted by the exhausted retina is called 
a physiological or accidental, color. In some persons the retina is 
incapable of distinguishing different colors, when they are said to 
be affected with "color-blindness." Thus, red and green may ap- 
pear alike, and then a cherry-tree, full of ripe fruit, will seem of the 
same color in every part. Railroad accidents have occurred because 
the engineer of the train, who was color-blind, has mistaken the 
color of a signal. {Read Note g. ) 

73, The Crystalline Lens. — Across the front of the eye, just 
behind the iris, is situated the crystalline lens, enclosed within its 
own capsule. It is supported in its place partly by a delicate circu- 
lar ligament, and partly by the pressure of adjacent structures. It 
is colorless and perfectly transparent, and has a firm but elastic 
texture. In shape, it is doubly convex, and may be rudely com- 
pared to a small lemon-drop. The front face of the lens is flatter 
than the other, and is in contact with the iris near its pupillary 
margin, as is represented in the diagram on page 257. It is only 
one-fourth of an inch thick. 

74. When this little body becomes opaque, and no longer affords 
free passage to the rays of light, as often happens with the advance 
of age, an affection termed " cataract " is produced. Between the 
crystalline lens and the cornea is a small space which contains the 

9. Color-blindness. — " Daltonism, or color-blindness, receives its name 
from the eminent English chemist, who described this infirmity as it existed 
in his own case. It arises from an unnatural condition of the organs of vision 
which prevents the discrimination of certain colors. Some persons will mis- 
take red for green ; so that ripe cherries on a tree appear the same as the 
leaves ; others recognize only black and white. Persons thus affected are 
sometimes incapable of discriminating musical tones. The healthy eye ordi- 
narily fails to discriminate between certain colors, blue and green especially, 
when viewed by artificial light. But even this may in a measure be overcome 
by training, so that an expert dealer in silk obtains a knowledge of the shades 
of blue, green, and violet, which is proof against the confusing influence of gas- 
light and tinted curtains. The eyes of persons who have much to do with 
colors are more liable to become overstrained than those dealing chiefly with 
rays of white light." — Flint's Physiology (in part). 



73. The location of the crystalline lens ? How supported ? Its color and texture ? 
Shape? Size? 

74. Cataract? Aqueous humor? Vitreous humor ? 



THE SPECIAL SENSES. 253 

aqueous humor (see Fig. 57, a). This humor consists of five or six 
drops of a clear, colorless liquid very much like water, as its name 
implies. That part of the globe of the eye lying behind the lens is 
occupied by the vitreous humor, so called from its fancied resem- 
blance to melted glass (Fig. 57, v). This humor is a transparent, 
jelly-like mass, enclosed within an exceedingly thin membrane. It 
lies very closely applied to the retina, or nervous membrane of the 
eye, and constitutes fully two-thirds of the bulk of the eyeball. 

75. The Uses of the Crystalline Lens. — A convex lens has 
the property of converging the rays of light which pass through it ; 
and the point at which it causes them to meet is termed its focus. 




^N 



The Retinal Image. 



If a lens of this description, such as a magnifying or burning-glass, 
be held in front of an open window, in such a position as to allow 
its focus to fall upon a piece of paper, it will be found to depict 
upon the paper a miniature image of the scene outside of the win- 
dow. It will be further noticed that the image is inverted, or up- 
side down, and that the paper at the place upon which the image is 
thrown is much brighter than any other part. 

76. Now all the transparent structures of the eye, but especially 
the crystalline lens, operate upon the retina, as the convex lens acts 
Mpon the paper — that is, they paint upon the retina a bright, in- 
Verted miniature of the objects that appear in front of the eye 
(Fig. 60). That this actually takes place may be proved by experi- 
ment. If the eyeball of a white rabbit, the walls of which are 

75. What is a lens and its focus ? The miniature image, how produced ? 

76. How are figures painted upon the retina ? How proved ? 



254 THE SPECIAL SENSES. 

transparent, be examined while a lighted candle is held before the 
cornea, an image of the candk-flame may be seen npon the retina. 

77. The form and structure of the crystalline lens endow it with 
a remarkable degree of refractive power, and enable it to converge 
all the rays of light that enter it through the pupil, to a focus 
exactly at the surface of the retina. When this lens is removed 
from the eye, as is frequently done for the cure of cataract, it is 
found that the rays of light then have their focus three-eighths of 
an inch behind the retina ; that the image is four times larger than 
in the healthy eye; that it is less brilliant, and that its outline is 
very indistinct. From this Ave learn that one of the uses of the 
crystalline lens is to. make the retinal image bright and sharply- 
defined, at the same time that it reduces its size. Indeed, the small 
size of the image is a great advantage, as it enables the limited sur- 
face of the retina to receive, at a glance, impressions from a con- 
siderable field of vision. 

78. As the image upon the retina is inverted, how does the 
mind perceive the object in its true, erect position? Many expla- 
nations have been advanced, but the simplest and most satisfactory 
appears to be found in the fact that the retina observes no differ- 
ence, so to speak, between the right and left or the upper and lower 
positions of objects. In fact, the mind is never conscious of the 
formation of a retinal image, and until instructed, has no knowledge 
that it exists. Consequently, our knowledge of the relative loca- 
tion of external objects must be obtained from some other source 
than the retina. The probable source of this knowledge is the 
habitual comparison of those objects with the position of our own 
bodies ; thus, to see an elevated object, we know we must raise the 
head and eyes ; and to see one at our right hand, we must turn the 
head and eyes to the right. 

79. Long-sight or Hyperopia, and Short-sight or Myopia. — 
The eye is not in all cases perfectly formed. For example, persons 
may from birth have the cornea too prominent or too flat, or the 
lens may be too thick or too thin. In either of these conditions 
sight will be more or less defective from the first, and the defect 

77. What can be said in respect to the form and structure of the crystalline lens ? 

78. How is the inverted image upon the retina presented in its true position to the mind? 

79. The uuilorm perfection of the eye ? Examples ? The most common imperfection ? 



THE SPECIAL SENSES. 255 

will not tend to disappear as life advances. The most common 
imperfection, however, is in the shape of the globe ; which may be 
short (Fig. 61, h), as compared with the natural eye, n, or it may 
be too long, m. 

80. When the globe is short, only objects that are at a distance 
can be clearly seen, and the condition of the vision is known as 
" long-sight," or hyperopia. It will be observed, by reference to 
Fig. 61, that the focus of the rays of light would fall behind the 
retina of this eye. When the globe is too long, only objects that 




Fig. 61.— The Different Shapes of the Globe of the Eye. 

N, The Natural Eye. M, The Short-sighted Eye. 

H, The Long-sighted Eye. S, Parallel Rays from the Sun. 

are very near to the eye can be clearly seen, and the condition 
resulting from this defect is termed " short-sight," or myopia. The 
focus of the rays of light is, in this case, formed in the interior of 
the eye in front of the retina. 

81. Long-sight, or hyperopia, is common among school-children, 
nearly as much so as short-sight, and must not be confounded with 
the defect known as the " far sight " of old people ; although in both 
affections the sight is improved by the use of convex glasses. 
Children not infrequently discover that they see much better when 
they chance to put on the spectacles of old persons. For the relief 
of short-sight, concave glasses should be employed ; as they so 
scatter the rays of light as to bring the focus to the retina, and thus 
cause the vision of remote objects to become at once distinct. That 
form of " squint," in which the eyes are turned inward, is generally 

80. How is " long-sight ' explained? "Short-sight?" 

81. Long-sight, how common ? With what must it not be confounded ? Kind of glassy 
for short-sight? Why? Squint? 



256 THE SPECIAL SENSES. 

dependent upon long-sight, while that rarer form, when they turn 
outward, is due to short-sight. {Read Note 10. ) 

82. The Function of Accommodation. — If, after looking 
through an opera-glass at a very distant object, it is desired to view 
another nearer at hand, it will be found impossible to obtain a clear 
vision of the second object unless the adjustment of the instrument 
be altered, winch is effected by means of the screw. If an object, 
like the end of a pencil, be held near the eye, in a line with another 
object at the other side of the room, or out of the window, and the 
eye be fixed first upon one and then upon the other, it will be found 
that when the pencil is clearly seen, the further object is indistinct ; 
and when the latter is seen clearly, the pencil appears indistinct, and 
that it is impossible to see both clearly at the same time. Accord- 
ingly, the eye must have the capacity of adjusting itself to distances, 
which is in some manner comparable to the action of the screw of 
the opera-glass. 

83. This, which has been called the function of accommodation, 
is one of the most admirable of all the powers of the eye, and is 
exercised by the crystalline lens. It consists essentially in a change 
in the curvature of the front surface of the lens, partly through its 

10. On the Production of Short-Sight. — " The observations of Cohn 
in the schools and University of Breslau, of Kruger in Frankfort-on-the-Main, 
of Erismann in St. Petersburgh, of Von Hoffmann in Wiesbaden, and others 
abroad, prove most conclusively that one of the bad effects of school and college 
life is to produce diseases of the eyes. They have shown that near-sightedness 
increases rapidly in frequency as you go up in the scale of schools from the 
primaries of the rural districts to the universities. The gravity of this finding 
may be appreciated when we remember that near-sightedness is a disease, and 
that it very frequently descends from one generation to another, marked by 
such organic changes in the eyes as tend to the production of the worst forms 
of the malady, and to blindness. In 1867, Cohn, of Breslau, published the 
results of the examination of the eyes of 10,060 scholars. His examinations 
covered the entire range of school-life. He found that 1,750 of the 10,060 
children had defective vision — about seventeen per cent. He also examined, 
without selection, 410 of the 964 students of the Breslau University, and found 
that not one-third had normal eyes." — Br. C. R. Agnew. 



82. What is stated in connection with the opera-glass ? Experiment with pencil and dis- 
tant object? 

83. Function of accommodation? In what does it consist? How is the function 
explained ? 



THE SPECIAL SENSES. 257 

own elasticity, and partly through the action of the ciliary muscle. 
When the eye is at rest — that is, when accommodated for a distant 
0D ject — the lens is natter and its curvature diminished (see Fig. 62) ; 
but when strongly accommodated for near vision, the lens becomes 
thicker, its curvature increases, and the image on the retina is made 
more sharp and distinct. Since a strong light is not required in 




Fig. 62. — The Function of Accommodation. 



The right half of the diagram shows the eye at rest. The left half shows the lens 
accommodated for near vision. 

viewing near objects, the pupil contracts, as is shown in the left- 
hand half of the diagram. 

84. Old-sight, OP Presbyopia. — But this marvelously beautiful 
mechanism becomes worn with use ; or, more strictly speaking, the 
lens, like other structures of the body, becomes harder with the ap- 
proach of old age. The material composing the lens becomes less 
elastic, the power to increase its curvature is gradually lost, and as a 
consequence, the person is obliged to hold the book further away 
when reading, and to seek a stronger light. In a word, the function 
of accommodation begins to fail, and is about the first evidence that 
marks the decline of life. By looking at the last preceding dia- 
gram, and remembering that the increased curvature of the lens 
cannot take place, it will be at once understood why old-sight is 
benefited in near vision by the convex lens, such as the spectacles 
of old people contain. It acts as a substitute for the deficiency of 
the crystalline lens. {Read Note n.) 

11. The Choice of Glasses. — "The perfectly healthy, normal eye, 
begins to need a glass for ordinary work at between forty and forty -fivo years 

S4. Change of sight with the approach of old age ? Explain the change ? 



V 



258 THE SPECIAL SENSES. 

85. The Sense of Heaping — Sound. — Hearing is the special 
sense by means of which we are made acquainted with sound. 
What is sound 1 It is an impression made upon the organs of hear- 
ing, by the vibrations of elastic bodies. This impression is com- 
monly propagated by means of the air, which is thrown into 
delicate undulations in all directions from the vibrating substance. 
"When a stone is thrown into smooth water, a wave of circular form 
is set in motion from the point where the stone struck, which, as it 
advances, constantly increases in size and diminishes in force. 

86. Somewhat resembling this is the undulation, or sound-wave, 

of age — of course, we here exclude all debilitated conditions of the body result- 
ing from disease. Now, then, comes the question — shall we put on glasses, 
and of what strength ? To answer some prevalent fallacies handed down from 
one generation to another, we cannot do better than quote from the highest 
authority, Prof. Donders, who says : ' The opinion is rather general that we 
should refrain as long as possible from the use of convex glasses. But, is it 
not folly to weary the eyes and the mind together, without necessarily con- 
demning ourselves to guess, with much trouble, at the forms which we could 
see pretty well with glasses ?' 

"Strangely enough, people have fallen also into the opposite fault. Some 
have thought, by the early use of spectacles, to be able to preserve their power 
of vision, and have recommended and employed ' conservative glasses. ' If I 
am not mistaken, self-interest had something to do with this recommendation. 
So long as the eye does not err, and remains free from fatigue in the work re- 
quired of it, its own power is sufficient, and it is inexpedient to seek assistance 
in the use of convex glasses. Having made up their minds that they require 
glasses, how are they to know what glasses to procure, or what number is cor- 
rect ? Generally, people go to the nearest spectacle- vender, and purchase what 
they see best with at the time. We say distinctly, once for all, that the 
ophthalmic surgeon is the one to be consulted as to the wearing of glasses. 
He, by testing the eye, can alone decide whether any, and what glasses, should 
be worn. Opticians and spectacle-venders know nothing about the laws which 
govern the refraction and accommodation of the eye. It is not their business, 
any more than it is the apothecary's to know about disease. The advice of the 
ophthalmic surgeon will also be found invaluable as to how to wear glasses, 
whether springs or spectacles, so as not to fatigue the eyes by straining them 
from improper use of these invaluable aids to man's happiness. "We conclude 
by saying, that all advice in this article applies to those having normal, 
heal thy, strong eyes." — Dr. B. Joy Jeffries. 



85. Hearing? What is sound ? How propagated commonly ? Stone thrown in water? 

86. Soi>nd-w;we in the atmosphere? Its shape? Rate of motion ? Sound, in water, air, 
and solid bodies ? 



THE SPECIAL SENSES. 



25$ 



which is imparted by a sonorous vibration to the surrounding 
atmosphere. Its shape, however, is spherical, rather than circular, 
since it radiates upward, downward, and obliquely, as well as hori- 
zontally, like the wave in water. The rate of motion of this 
spherical wave of air is about 1,050 feet per second, or one mile in 
five seconds. In water, sound travels four times as fast as in air, 
and still more rapidly through solid bodies ; along an iron rod its 
velocity is equal to two miles per second. 

87. The earth, likewise, is a good conductor of sound. It is said 
that the Indian of our western prairies can, by listening at the sur- 
face of the ground, hear the advance of a troop of cavalry while 
they are still out of sight, and can even discriminate between their 
tread and that of a herd of buffaloes. Solid substances also convey 
sounds with greater power than air. If the ear be pressed against 
one end of a long beam, the scratching of a pin at the other 
extremity may be distinctly heard, which will not be at all audible 
when the ear is removed from the beam. Although air is not the 
best medium for conveying sound, it is necessary for its production. 
Sound cannot be produced in a vacuum, as is shown by ringing a 
bell in the exhausted receiver of an air-pump, for it is then entirely 
inaudible. But let the air be re-admitted gradually, then the tones 
become more and more distinct, and when the receiver is again full 
of air, they will be as clear as usuaL 

88. All sonorous bodies do not vibrate with the same degree of 
rapidity, and upon this fact depends the pitch of the sounds that 
they respectively produce. The more frequent the number of 
vibrations within a given time, the higher will be the pitch ; and 
the fewer their number, the lower or graver will it be. Now, the 
rate of the successive vibrations of different notes has been meas- 
ured, and it has thus been found that if they are less than sixteen 
in a second, no sound is audible; while, if they exceed 60,000 per 
second, the sound is very faint, and is painful to the ear. The ex- 
treme limit of the capacity of the human ear may be considered as 
included between these points, but the sounds which we ordinarily 
hear are embraced between 100 and 3,000 vibrations per second. 

87. The earth as a conductor of sound? What has the western Indian hcen taught? 
Solid substances as conductors ? As regards sound, in what respect is air necessary ? Sound 
in a vacuum ! 

88. l.'itch, To what due? Capacity of ear? 



260 



THE SPECIAL SENSES. 



89. The ear, which is the proper organ of hearing, is the most 
complicated of all the structures that are employed in the reception 
of external impressions The parts of which it is composed are 
numerous, and some of them are extremely small and delicate. 
Nearly all these parts are located in an irregularly shaped cavity 
hollowed out in the temporal, or " temple " bone of each side of the 
head. That part of the bone in which the auditory cavity is placed 
has the densest structure of all bones of the body, and has, there- 
fore, been called the " petrous," or rocky part of the temporal bone. 
In studying the ear, it is necessary to consider it as divided into 




Fig. 63.— The Ear and its Different Parts. 
A, Diagram of the Ear. 
a, i, External Ear. d, Middle Ear. 

c, Membrana tympani. e, Internal Ear. 

B to B'", Bones of the Middle Ear (magnified). 

C, The Labyrinths, or Internal Ear (highly magnified). 

three portions, which are called, from their relative positions, the 
external ear, the middle ear, and the internal ear. (In the diagram, 
Fig. 63, a, the first is not shaded, the second is lightly shaded, and 
the last has a dark background.) 

90. The External Ear. — The external portion of the organ of 
hearing, designated in Fig. 63, a, includes, first, that outer part 
(a), which is commonly spoken of as " the ear," but which in fact 

89. The ear. Its divisions. 

90. Of what does the external portion of the organ of hearing consist? Describe tl e 
portal of that organ known as the ear. Its use ? 



THE SPECIAL SENSES. 261 

is only the portal of that organ ; and, secondly, the auditory canal 
(b). The former consists of a flat, flexible piece of cartilage, pro- 
jecting slightly from the side of the head, attached to it by liga- 
ments, and supplied with a few weak muscles. Its surface is 
uneven, and curiously curved, and from its resemblance to a shell, 
it has been called the concha. It probably serves to collect sounds, 
and to give them an inward direction, although its removal is said 
not to impair the acuteness of hearing more than a few days. 

91. In those animals whose hearing is more delicate than that of 
man, the corresponding organ is of greater importance, it being 
larger, and supplied with muscles of greater power, so that it serves 
as a natural kind of ear-trumpet, which is easily movable in the 
direction of any sound that attracts the attention of £he animal. 
Bold, preying animals generally have the concavity of this organ 
directed forward, while in timorous animals, like the jg&bft, it is 
directed backward. Fishes have no outer ear, but soiui^^af e trans- 
mitted directly through the solid bones of the head, to ^he internal 
organ of hearing. 

92. The auditory canal (Fig. 63, a, b), which is continuous with 
the outer opening of the ear, is a passage an inch and a quarter in 
length, its inner extremity being bounded by a closely-fitting, cir- 
cular membrane. This canal is of oval form, is directed forward 
and inward, and is slightly curved, so that the inner end is ordi- 
narily concealed from view. The pouch of the skin which lines this 
passage is smooth and thin, especially at the lower end, where it 
covers the membrane just mentioned. 

93. As in the case of the nostrils, a number of small, stiff hairs 
garnish the margin of the auditory canal, and guard it, to some 
extent, against the entrance of insects and other foreign objects 
The skin, too, covering its outer half, is furnished with a belt of 
little glands which secrete a yellow, bitter substance, called " ear- 
wax," which is especially obnoxious to small insects. As the outer 
layer of this wax-like material loses its useful properties it becomes 
dry, and falls out of the ear in the form of minute, thin scales, a 
fresh supply being furnished from the little glands beneath. In its 

91. The ear in the animals of delicate hearing ? Rabbit ? Fishes ? 

92. What is the auditory canal ? Describe it ? 

93. How is it guarded and protected ? Ear-wax? 



262 



THE SPECIAL SENSES. 



form, the auditory canal resembles the tube of an ear-trumpet, and 
serves to convey the waves of sound to the middle portion of the 
ear. 

94. The Middle Ear, op Tympanum. — The middle ear is a 
small cavity, or chamber, of irregular shape, about one-fourth of an 
inch across from side to side, and half an inch long (see Fig. 63, 
a, d), From the peculiar arrangment of its various parts it has 



x- X . ^ 




Fig. 64. — Showing the Internal Mechanism of the Ear (greatly enlarged) 

very properly been called the tympanum, or the " drum of the ear." 
\ The middle ear, like the external canal, contains air. 
\ - -J95. The circular membrane, already mentioned as closing the 
\ auditory canal, is the partition which separates the middle from the 
external ear, and is called the membrana tympani (c), and may be 
considered as the outer head of the drum of the ear. It is some- 
times itself spoken of as the " drum," but this is incorrect, since a 
drum is not a membrane, but is the hollow space across which the 
membrane is stretched. Tins membranous drum-head is very tense 
and elastic, and so thin as to be almost transparent ; its margin is 
fastened into a circular groove in the adjacent bone. Each wave of 



94. What is the middle ear? Why called tympanum ? 

95. What is the inenibrana tympani ? Describe it. 



THE SPECIAL SENSES. 263 

sound that touches this delicate membrane causes it to vibrate, 
and it, in turn, excites movements in the parts beyond. 

96. Within the tympanum is arranged a chain of remarkable 
" little bones," or ossicles. They are chiefly three in number, and 
from their peculiar shapes bear the following names : malleus, or 
the mallet; incus, or the anvil; and stapes, or the stirrup. A fourth^ 
the smallest bone in the body, in early life intervenes between the 
incus and stapes, but at a later period it becomes a part of the 
incus. It is called the orbicular bone. Small as are these ossicles 
— and they, together, weigh only a few grains — they have their 
little muscles, cartilages, and blood-vessels, as perfectly arranged as 
the larger bones of the body. One end of the chain of ossicles, the 
mallet, is attached to the membrane of the tympanum, or outer 
drum-head, while the other end, the stirrup, is firmly joined by its 
foot-piece to a membrane in the opposite side of the cavity. The 
chain, accordingly, hangs suspended across the drum between the 
two membranes; and when the outer one vibrates under the influ- 
ence of the sound-wave, the chain swings inward and transmits the 
vibration to the entrance of the inner ear. 

97. The musical instrument, the drum, is not complete if the 
air within be perfectly confined ; we therefore find in all instru- 
ments of this kind a small opening in the side, through which air 
may pass freely. By this means the pressure of the air upon the 
vellum which forms the head of the drum is made equal upon all 
sides, and the resonance of the drum remains unaffected by the 
varying density of the atmosphere. It will, therefore, emit its 
proper sound, whether it be struck in the rarefied air of the 
mountain-top, or in the condensed air of a mine. The tympanum, 
or drum of the ear, in like manner has an opening, by means of 
which it communicates freely with the external air. This opening 
is a narrow canal, about an inch and a half long, called the 
Eustachian tube, after the name of its discoverer, Eustachius. 

98. The course of this passage is indicated in Fig. 64, directed 
downward and inward : its other extremity opens into the upper 



96. What are the ossicles ? Their number and names ? Their arrangement ? 

97. The Eustachian tube ? Describe it, and state its use. 

98. What can you state of the action of the Eustachian tube 1 



264 



THE SPECIAL SENSES. 



part of the throat. The passage itself is ordinarily closed, but 
whenever the act of swallowing or gaping takes place, the orifice in 
the throat is stretched open, and the air of the cavity of the 
tympanum may then be renewed. Air may at will be made to enter 
through this tube, by closing the mouth and nose, and then trying 




Fig. 65. 



A, The Concha. 

B, Auditory Canal. 

C, Membrane of the Drum. 

(the lower half.) 

D, A Small Muscle. 



Section of the Right Ear. 

E, 



Incus, or Anvil. 
M, Malleus, or Mallet. 
I, Eustachian Tube. 
G, Semicircular Canals. 
H, Cochlea, or Snail's ShelL 



to force air through the latter. When this is done, a distinct 
crackle or clicking sound is perceived, due to the movement of the 
membranes, and of the little bones of the ear. 

99. The Eustachian tube serves, also, as an escape-pipe for the 
fluids which form within the middle ear ; and hence, when its lining 
membrane becomes thickened, in consequence of a cold or sore 
throat, and the passage is thus more or less choked up, the fluids 
are unable to escape as usual, and therefore accumulate within the 



99. What other purpose does the Eustachian tube serve ? How is this shown? " Throat- 
deafness ?" Primary use of the Eustachian tube 1 



THE SPECIAL SENSES. 265 

ear. When this takes place, the vibrations of the membrane are 
interfered with ; the sounds heard appear muffled and indistinct ; 
and a temporary difficulty of hearing, which is known as " throat- 
deafness," is the result. This result resembles the effect produced 
by interrupting the vibrations of a sonorous body, such as all are 
familiar with ; if the finger be placed upon a piano-string or bell 
when it is struck, the proper sound is no longer fully and clearly 
emitted. But the primary use of this tube is to afford a free com- 
munication between the middle ear and the external atmosphere, 
and thus secure an equal pressure upon both sides of the membrane 
of the drum of the ear, however the density of the atmosphere may 
vary. If, from undue tension of the membrane, pain is experienced 
in the ears, when ascending into a rare atmosphere, as in a balloon, 
or descending into a dense one, as in a diving-bell, it may be 
relieved by repeating the act of swallowing, from time to time, 
in order that the inner and outer pressure may thus be promptly 
equalized. 

100. The Internal Ear, op Labyrinth. — The most essential part 
of the organ of hearing is the distribution of the auditory nerve. 
This is found within the cavity of the internal ear, which, from its 
exceedingly winding shape, has been termed the labyrinth (see Fig. 
64, c). This cavity is hollowed out in dense bone, and consists of 
three parts — the vestibule (a), or ante-chamber, which is connected 
with the other two ; the cochlea (b), or snail's shell ; and the three 
semicircular canals (c). The manner in which the nerve of hearing 
is distributed is remarkable, and is peculiar to this nerve. In the 
vestibule and the canals its fibres are spread out over the inner 
surface, not of the bony cavity, but of a membranous bag, 
which conforms to and partially fills that cavity, and which 
floats in it, being both filled and surrounded with a clear, limpid 
fluid. 

101. A singular addition to the mechanism of hearing is observed 
within this membranous bag of the labyrinth. This consists of two 
small oval ear-stones, and a quantity of fine powder of a calcareous 
nature, which is called " ear-sand." When examined under the 



100. The essential part of the organ of hearing ? Its location ? Formation ? 

101. Where is the " ear-sand " found ? Give the theory as to its use. 



12 



266 THE SPECIAL SENSES. 

microscope, these sandy particles are seen to lie scattered upon and 
among the delicate filaments of the auditory nerve ; and it is prob- 
able that, as the tremulous sound-wave traverses the fluid of the 
vestibule, the sand rises and falls upon the nerve-filaments, and thus 
intensifies the sonorous impression. 

102. In the cochlea, or snail's shell, which contains the fluid, but 
no membrane, the nerve branches upon a spiral shelf, which, like 
the cochlea itself, takes two and a half turns, growing continuously 
smaller as it winds upward. As many as three thousand nerve- 
fibres of different lengths have been counted therein ; these, it has 
been thought, form the grand, yet minutely small key-board, upon 
which strike all the musical tones that are destined to be conveyed 
to the brain. The vestibule, it is also supposed, takes notice of 
noise as distinguished from musical sounds ; while the office of the 
semicircular canals is, in part at least, to prevent internal echoes, or 
reverberations. 

103. The vestibule communicates with the chain of bones of the 
middle ear by means of a small opening, called the " oval window," 
or fenestra ovalis. Across this window is stretched the membrane, 
which has already been alluded to as being joined to the stirrup- 
bone of the middle ear. Through this window, then, the sound- 
wave, which traverses the external and middle ear, arrives at last at 
the labyrinth. The limpid fluid which the latter contains, and which 
bathes the terminal fibres of the nerve of hearing, is thus agitated, 
the nerve-fibres are excited, and a sonorous impression is conducted 
to the brain, or, as we say, a sound is heard. 

104. Protection of the Sense of Hearing. — From what has 
been seen of the complicated parts which compose the organ of 
hearing, it is evident that while many of them possess an exquisite 
delicacy of structure, Nature has well and amply provided for their 
protection. We have observed the concealed situation of the most 
important parts of the mechanism of the ear — the length of its cavity, 
its partitions, the hardness of its walls, and its communication with 

102. In the cochlea, or snail's shell ? ' ' Key-board " in the internal ear ? The vestibules ? 
Semicircular canals ? 

103. With what does the vestibule communicate? What is the theory by which sound is 
conducted to the brain ? 

104. The formation of the organ of hearing with a view to its protection 7 



THE SPECIAL SENSES. 267 

the atmosphere ; all these provisions rendering unnecessary any 
supervision or care on our part in reference to the interior of the ear. 
But in respect to its external parts, which are under our control and 
within the reach of harm, it is otherwise. We may both observe 
the dangers which threaten them, and learn the means necessary to 
protect them. 

105. Caution. — One source of danger to the hearing consists in 
lowering the temperature of the ear, especially by the introduction 
of cold water into the auditory canal. Every one is familiar 
with the unpleasant sensation of distension, and the confusion of 
sounds which accompany the filling of the ear with water when 
bathing : the weight of the water within it really distends the 
membrane, and the cold chills the adjacent sensitive parts. It 
is not surprising, therefore, that the frequent introduction of cold 
water, and its continued presence in the ear, enfeebles the sense 
of hearing. Care should be taken to remove water from the ear 
after bathing, by holding the head on one side, and, at the same 
time, slightly expanding the outer orifice, so that the fluid may 
run out. For a like reason, the hair about the ears should not 
be allowed to remain wet, but should be thoroughly dried as soon 
as possible. 

106. It may be stated as a general rule, to which there are but 
few exceptions, that no cold liquid should ever be allowed to enter 
the ear. When a wash or injection is rendered necessary, it should 
always be warmed before use. The introduction of cold air is like- 
wise hurtful, especially when it pours through a crevice directly into 
the ear, as it may often do through the broken or partially closed 
window of a. car. The avoidance of this evil gives rise to anothei 
almost as great, namely, the introduction of cotton or other soft 
substances into the ear to prevent it from " catching cold." This 
kind of protection tends to make the part unnaturally susceptible 
to changes of temperature, and its security seems to demand the 
continued presence of the " warm " covering. As a consequence of 
its presence, sounds are not naturally conveyed, and the sensitive- 
ness of the nerve of hearing is gradually impaired. 

105. Danger to which the hearing may be subjected ? Advice ? 

106. The general rule as to the use of water for the ear? 



268 THE SPECIAL SENSES. 

107. The chief source of injury, however, to the ear is from the 
introduction of solid substances into the auditory canal, with the 
design of removing insects or other foreign objects that have found 
their way into the ear, or with the design of scraping out the ear- 
wax. For displacing a foreign object, it is usually sufficient to 
syringe the ear gently with warm water, the head being so held 
that the fluid easily escapes. If a live insect has gained entrance 
to the ear. it may first be suffocated by pouring a little oil upon 
it, and afterward removed by syringing tha ear as just men- 
tioned. 

108. The removal of ear-wax is generally unnecessary ; for, as 
we have before seen, Nature provides that the excess of it shall be- 
come dry, and then spontaneously fall out in the form of fine scales. 
The danger from the introduction of solid implements into the outer 
ear is chiefly found in the fact that the membrane which lies at the 
bottom of it is very fragile, and that any injury of it is liable to 
impair permanently the hearing of the injured ear. {Read Note 12.) 



12. How the Organs of Hearing may be Injured. — "There are 
several things very commonly done which are extremely injurious to the ear, 
and ought to be carefully avoided. And first, children's ears ought never to 
be boxed. We have seen that the passage of the ear is closed by a thin mem- 
brane, especially adapted to be influenced by every impulse of the air. If any 
one designed to break the membrane, he could scarcely devise a more effective 
means than to bring the hand suddenly down upon the outer ear, thus 
driving the air violently before it, with no possibility for its escape but by the 
membrane giving way. And far too often permanent deafness has thus been 
produced. Three things should be remembered here : 1. That slight degrees 
of deafness, often lasting only for a time, are very common among children, 
especially during or after colds. 2. That a slight deafness, which does' not 
prevent a person from hearing when he is expecting to be spoken to, will make 
him very dull to what he is not expecting ; and 3. That there is a kind of 
deafness in which a person can hear pretty well while listening, but is really 
very hard of hearing when not listening. All sorts of substances are some- 
times put into the ear by children, who do it to themselves or to each other in 
ignorant play. If every parent and teacher warned his children against doing 
this, it would not be a useless precaution. "When the accident happens, 
the chief danger is that of undue haste and violence. Such bodies should 



107. Chief source of injury to the ear ? Directions for removing foreign objects from the* 
ear? Of a live insect? 



THE SPECIAL SENSES. 269 

be removed by syringing with warm water alone, and no attempt should be 
made to lay hold of them or move them in any other way. Now, no cold 
fluid should ever enter the ear ; cold water is more or less irritating, and if 
used for syringing rapidly produces extreme giddiness. "Washing the ear out 
with soap and water is bad. The use of any thing hard or stiff to clean out 
the wax is improper. If there is any desire to do so, it shows that the ear is 
unhealthy, and it wants soothing, not picking. Now and then an insect gets 
into the ear and causes great pain ; the way to get rid of it is to pour oil into 
the ear. This suffocates the insect." — Physiology for Practical Use. 



270 THE SPECIAL SENSES. 

QUESTIONS FOR TOPICAL REVIEW. 

PACK 

1. What is said of the production of sensation ? 220 

2. What is said of the variety of sensations ? 221 

3. What is said of the general sensibility ? 221 

4. What is said of the sensation of pain 222 

5. What is said of the uses of pain ? 223 

6. Say what you can of the special sensation 225 

7. Say what you can of the organs of touch , 227 

8. Say what you can of the sense of touch 228 

9. Say what you can of the delicacy of touch 229 

10. What is understood by the sensations of temperature and weight ? 230 

11. What is understood by the organ of taste ? 232 

12. What is understood by the sense of taste ? 233 

13. What is understood by the relations of taste ? 234 

14. Explain the influence of education, etc 235 

15. Explain the sense of smell 235 

16. Explain the nerve of smell 236 

17. Explain the uses of the sense of smell 237 

18. Explain the sense of sight 240 

19. Give the statement concerning light and the optic nerve 240, 241 

20. Give the statement concerning the organ of sight 242 

21. Give the statement concerning the orbits 242, 243 

22. Give the statement concerning the eyelids 243 

23. Give the statement concerning the lachrymal fluid 244, 245 

24. Give the statement concerning the eyeball 246 

25. Give the statement concerning the iris 248 

26. Give the statement concerning the retina 249, 250, 251 

27. Give the statement concerning the crystalline lens 252 

28. What are the uses of the lens ? 253, 254 

29. What about long and short sight? 254,255 

30. Explain the function of accommodation 256, 257 

31. Explain old sight, or presbyopia 257 

32. Explain hearing and sound . 25S, 259, 260 

33 Explain the external ear .- 260,261 

34. Explain the middle ear? 262, 263, 264 

35. Explain the internal ear 265, 266 

36. What is said of the protection of the sense of hearing? 266 

37. What caution is given ? ., 267, 26€ 



CHLAJPTJffiR XI. 

The Voice. 

Voice and Speech — The Larynx, or th», Organ of the Voice — The Vocal Cords— 
The Laryngoscope — The Production of the Voice — The Use of the Tongue — 
The Different Varieties of Voice — The Change of Voice — Its Compass — . 
Purity of Tone — Ventriloquy. 

1. Voice and Speech. — In common with the majority of the 
nobler animals, man possesses the power of uttering sounds, which 
are employed as a means of communication and expression. In man, 
these sounds constitute the voice ; in the animals they are desig- 
nated as the cry. The song of the bird is a modification of its cry, 
which is rendered possible from the fact that its respiratory function 
is remarkably active. The sounds of the animals are generally pro- 
duced by means of their breathing organs. Among the insects, 
they are sometimes produced by the extremely rapid vibrations of 
the wings in the act of night, as in the case of the mosquito ; or by 
the rubbing together of hard portions of the external covering of 
the body, as in the cricket. Almost all kinds of marine animals 
are voiceless. The tambour-fish and a few others have, however, 
the power of making a sort of noise in the water. {Read Note 1. ) 

2. But man alone possesses the faculty of speech, or the power 
to use articulate sounds in the expression of ideas, and in the com- 

1. Voice in Man and Animals. — " The human voice, taking male and 
female together, has a range of nearly four octaves. Man's power of speech, 
or the utterance of articulate sounds, is due to his intellectual development 
more than to any great structural difference between him and the Apes. Song 
is produced by the glottis, speech by the mouth. The parrot and mocking- 
bird use the tongue in imitating human sounds." — Orion's Zoology. 



1. The uttering of sounds by animals ? How produced ? 

2. The evidence of man's superior endowment? What is stated of the idiot ? Parrot? 
Raven? 



272 THE VOICE. 

munication of mind with mind. Speech is thus an evidence of the 
superior endowment of man, and involves the culture of the intellect. 
An idiot, while he may have complete vocal organs and full power 
of uttering sounds or cries, is entirely incapable of speech ; and, as 
a rule, the excellence of the language of any people will be found 
to be proportional to their development of brain. Man, however, 
is not the only being that has the power to form articulate sounds, 
for the parrot and the raven may also be taught to speak by rote ; 
but man alone attaches meaning to the words and phrases he em- 
ploys. 

3. Relation to Hearing. —Speech is intimately related to the 
sense of hearing. A child born deaf is, of necessity, dumb also ; 
not because the organs of speech are imperfect, for he can utter 
cries and may be taught to speak, and even to converse in a rude 
and harsh kind of language; but because he can form no accurate 
notion of sound. A person, whose hearing is not delicate, or as 
it is commonly expressed, who " has no ear for music," cannot sing 
correctly. A person who has impaired hearing commonly talks in 
an unnaturally loud and monotonous voice. These examples show 
the necessary relation of intelligence and the sense of hearing with 
that form of articulate voice, which is termed speech. {Read Note 2.) 

2. Certain Peculiarities of the Voice. — "Voice is a sound produced 
in the throat by the passage of the air through the glottis, as it is expelled 
from the lungs. It is grave and strong in man, soft and higher in women ; 
it varies according to age. It is alike in both sexes in infancy, but is modified 
in youth ; then the voice is said to ' change. ' In the young woman it descends 
a note or two, and becomes stronger. In the young man the change is much 
more strongly marked. At the fourteenth or fifteenth year the voice loses its 
regularity, becomes harsh and unequal ; the high notes cannot be sounded, 
while the grave ones make their appearance. A year is generally sufficient for 
this change to be complete, and the voice of the child gives place to that of 
the man. Exercise of the voice in singing should be very moderate, if not 
entirely snspended, while this change is going on. Yoice is divided into sing- 
ing and speaking voice. One differs from the other almost as much as noises 
do from musical sounds. It is the short duration of speaking sounds which 
distinguishes them from those of singing. This is proved by the fact that if 
we prolong the intonation of a syllable, or utter it like a note, the musical 



3. Speech and hearing? A deaf child ? Person having "no ear for music?" Impaired 
hearing? What do the examples show? 



THE VOICE. 273 

4. The Organ of the Voice. — The essential organ of the voice 
is the Larynx. This has been previously alluded to in its relation 
to the function of respiration ; and, in the chapter on that subject, 
are figured the front view of that organ (Fig. 42), and its connec- 
tion with the trachea, tongue, and other neighboring parts (Fig. 45). 
It is situated at the upper part of the neck, at the top of the 
trachea, or tube by which air passes into and out of the lungs. The 
framework of the larynx is composed of four cartilages, which ren- 
der it at once very strong and sufficiently flexible to enable it to 
move according to the requirements of the voice. 

5. The names of the cartilages are (1) the thyroid, which is a 
broad, thin plate, bent in the middle and placed in the central line 
of the front part of the neck, where it is known as the pomum 
Adami, or Adam's apple (Fig. 66, b), and where it may be felt 
moving up and down with each act of swallowing ; (2) the cricoid, 
which is shaped like a seal ring, with the broad part placed poste- 
riorly (Fig. 66, e). At the top of the cricoid cartilage are situated 
the two small arytenoid cartilages, the right one of which is shown 
in Fig. 66, c. These latter little organs are much more movable 

sound becomes evident And if we pronounce all the syllables of a phrase in 
the same tone, the speaking voice closely resembles psalm-singing. Every one 
must have noticed this in hearing school-boys recite or read in a monotone, 
and the analogy is complete when the last two or three syllables are pro- 
nounced in a different tone. Spoken voice is moreover always a chant more 
or less marked, according to the individual and the sentiment expressed. The 
accentuation peculiar to certain languages also gives the speech the character 
of a chant ; to a French ear an Italian preacher seems always to sing. A chant 
also is caused by those inflections of the voice, which express our emotions and 
our passions. They extend from the feeble murmur, which the ear scarcely 
perceives, to the piercing cry of pain. Affectionate, sympathetic, imperious, 
or hostile, they sometimes charm, sometimes irritate, and always move us. It 
It is related of Gretry, that he amused himself by noting as exactly as pos- 
sible the ' Bonjour, monsieur ! ' of the persons who visited him ; and these 
words expressed by their intonation, in fact, the most opposite sentiments, 
although literally the same. Baron, the comedian, moved his audience to 
tears by his recitation of the stanzas of the song, ' Si le roi m'avait donne 
Paris sa grand'ville. ' — If the king had given me Paris his great city. " — Le 
Pileur on Wonders of the Human Body. 

4. Organ of the voice ? Where situated ? Of what is its framework composed ? 

5. Names, formation, and situation of the cartilages ? 



274 



THE VOICE. 



^t 



than the other two, and are very important in the production of the 
voice. They have a true ball-and-socket joint, and several small 
muscles which contract and relax with as 
perfect regularity and accuracy as any of the 
larger muscles of the body. 

6. The interior of the larynx is lined 
with a very sensitive mucous membrane, 
which is much more closely adherent tc 
the parts beneath than is usually the case 
with membranes of this description. " The 
epiglottis (a), consisting of a single leaf- 
shaped piece of cartilage, is attached to the 
front part of the larynx. It is elastic, easily 
moved, and fits accurately over the entrance 
to the air-passages below it. Its office is to 
guard these delicate passages and the lungs 
against the intrusion of food and other for- 
eign articles, when the act of swallowing 
takes place. It also assists in modifying 
the voice. 

7. The Vocal Cords. — Within the larynx, 
it from the thyroid car- 
tilage in front to the arytenoid cartilages 
behind, are placed the two sets of folds 
called the vocal cords. The upper of these, 
one on each side, are the false cords, which are 

comparatively fixed and inflexible. These are not at all essential to 
uhe formation of vocal sounds, for they have been injured, in those 
lower animals whose larynx resembles that of man, without mate- 
rially affecting their characteristic cries. Below these, one on each 
side, are the two vocal cords (Fig. 66, f), which pursue a similar 
direction to the false cords — namely, from before backward. They 
are composed of a highly elastic, though strong tissue, and are 
covered with a thin, tightly-fitting layer of mucous membrane. 
Their edges are smooth and sharply-defined, and when they meet, 




Fig. 66. — Section of the nrir | ctrpfrhprl r, Prn c« 
Larynx and Trachea. anCL sl:retcliea across 

A, The Epiglottis. 

B, The Thyroid Cartilage. 

C, Arytenoid Cartilage. 

D, Ventricle of the Larynx 

E, Cricoid Cartilage. 

F, Right Vocal Cord. 
H. The Trachea. 



6. Lining of the interior of the larynx ? The epiglottis ? 

7. Where are the vocal cords ? The false cords ? The true cords ? 



THE VOICE. 



275 



as they do in the formation of sounds, they exactly match each 
other. 

8. Between the true and false vocal cords is a depression on 
each side, which is termed the ventricle of the larynx (Fig. 66, d). 
The integrity of these true cords, and their free vibration, are essen* 
tial to the formation of the tones and the modulation of the natural 
voice. This is shown by the fact that, if one or both of these cords 
are injured or become diseased, voice and speech are weakened ; or 
when the mucous membrane covering them becomes thickened, in 
consequence of a cold, the vocal sounds are rendered husky and 
indistinct. When an opening is made in the throat below the 
cords — as not infrequently occurs in consequence of an attempt to 
commit suicide — voice is impossible except when the opening is 
closed by external pressure. 

9. The interval or space between the true cords of the voice is 
constantly varying, not only when their vocal function is in exer- 
cise, but also during the act of 

respiration. Every time the 
lungs are inflated, the space 
increases to make wide the 
entrance for the air, and di- 
minishes slightly during expi- 
ration. So that these little 
cords move gently to and fro 
in rhythm with the expansion 
and contraction of the chest 
in breathing. These move- 
ments and others may be seen FlG 
to take place, if a small mir- 
ror attached to a long handle be placed back into the upper part of the 
throat ; the handle near the mirror must be bent at an angle of 45°, 
so that we may look " around the corner," so to speak, behind the 
tongue. The position which the mirror must assume will be under- 
stood by reference in Fig. 45. A view of what may be seen under 




—A View of the Vocal Cords 
Means of the Laryngoscope. 



a Where is the ventricle of the larynx? The essentials to the formation of the tones 
and modulation of the voice ? 

9. Variation in the interval between the true cords of the voice ? Experiment with the 
mirror? 



276 THE VOICE. 

favorable circumstances, during tranquil inspiration, is represented 
in Fig. 67. The vocal cords are there shown as narrow, white 
bands, on each side of the central opening, and since the image is 
inverted, the epiglottis appears uppermost. The rings partly seen 
through the opening belong to the trachea. This little mirror is 
the essential part of an instrument, which is called the laryngoscope, 
and simple as it may seem, it is accounted one of the most valuable 
of the recently-invented appliances of the medical art. 

10. The Production of the Voice. — During ordinary tranquil 
breathing, no sound is produced in the larynx, true vocal tones 
being formed only during forcible expiration, when, by an effort of 






Fig. 68. — The Different Positions of the Vocal Cords. 
A., The position during inspiration. B, In the formation of low notes. C, In the formation 

of high notes. 

the will, the cords are brought close together, and are stretched so 
as to be very tense. The space between them is then reduced to a 
narrow slit, at times not more than y^-g- of an inch in width ; and 
the column of expired air being forced through it, causes the cords 
to vibrate rapidly, like the strings of a musical instrument. Thus 
the voice is produced in its many varieties of tone and pitch ; its 
intensity, or loudness, depending chiefly upon the power exerted in 
expelling the air from the lungs. When the note is high, the space 
is diminished both in length and width ; but when it is low, the 
space is wider and longer (Fig. 68, b, c), and the number of vibra- 
tions is fewer within the same period of time. 

II. The personal quality of the voice, or that which enables us 
to recognize a person by his speech, is mainly due to the peculiar 
shape of the throat, nose, and mouth, and the resonance of the air 
contained within those cavities. The walls of the chest and the 
trachea take part in the resonance of the voice, the air within 

10. The formation of true vocal tones ? 

11. To what is the personal quality of the voice mainly due ? What aids are there ? 



THE VOICE. 277 

them vibrating at the same time with the parts above them. This 
may be tested by touching the throat or breast-bone, when a strong 
vocal effort is made. The teeth and the lips also are important, as 
is shown by the unnatural tones emitted by a person who has lost 
the former, or by one who is affected with the deformity known 
as "hare-lip." The tongue is useful, but not indispensable to 
speech ; the case of a woman is reported, from wnom nearly the 
whole tongue had been torn out, but who could, nevertheless, speak 
distinctly and even sing. 

12. The Varieties of voice are said to be four in number; two, 
the bass and tenor, belonging to the male sex ; and two, the con- 
tralto or alto, and soprano, peculiar to the female. The baritone 
voice is the name given to a variety intervening between the bass 
and tenor. In man, the voice is strong and heavy ; i in woman, 
soft and high. In infancy and early youth, the voice is the same 
in both sexes, being of the soprano variety : that of boys is both 
clear and loud, and being susceptible of considerable training, is 
highly prized in the choral services of the church and cathedral. 
At about fourteen years of age the voice is said to change — that 
is, it becomes hoarse and unsteady by reason of the rapid growth 
of the larynx. In the case of the girl, the change is not very 
marked, except that the voice becomes stronger and has a wider 
compass ; but in the boy, the larynx nearly doubles its size in a 
single year, the vocal cords grow thicker, longer, and coarser, and 
the voice becomes masculine in character. During the progress of 
this change, the use of the voice in singing is injudicious. 

13. The ordinary range of each of the four varieties of the voice 
is about two octaves ; but this is exceeded in the case of several 
celebrated vocalists. Madame Parepa Eosa has a compass of three 
full octaves. When the vocal organs have been subjected to care- 
ful training, and are brought under complete control of the will, 
the tension of the cords becomes exact, and their vibrations become 
exceedingly precise and true. Under these circumstances the voice 
is said to possess " purity " of tone, and can be heard at a great dis- 
tance, and above a multitude of other sounds. The power of a 



12. Varieties of voice ? The baritone ? The voice in early youth ? 

13. The range of the voice ? Result of careful training of the vocal organs ? 



278 THE VOICE. 

pure voice to make itself heard was recently exemplified in a strike 
ing manner at a musical festival held in an audience-room of 
extraordinary size, and amid an orchestra of a thousand instruments 
and a chorus of twelve thousand voices, the artist named above also 
sang ; yet such was the purity and strength of her voice that its 
notes could be clearly heard rising above the vast waves of sound 
produced by the full accompaniment of chorus and orchestra. 
[Read Note 3. ) 

14. In the production of the articulate sounds of speech, the 
larynx is not directly concerned, but those sounds really depend 
upon alterations in the shape of the air-passages above that organ. 
That speech is not necessarily due to the action of the larynx is 
proved by the following simple experiment. Let an elastic tube 
be passed through the nostril to the back of the mouth. Then, 
while the breath is held, cause the tongue, teeth, and lips to go 
through the form of pronouncing words, and at the same time, let a 
second person blow through the tube into the mouth. Speech, pure 

3. The Benefits ofVocal Exercise. — " Reading aloud and recitation are 
more useful and invigorating musical exercises than is generally imagined, atleast 
when managed with due regard to the natural powers of the individual, so as 
to avoid effort and fatigue. Both require the varied activity of most of the 
muscles of the trunk to a degree of which few are conscious, till their attention 
is turned to it. In forming and undulating the voice, not only the ohest, but 
also the diaphragm and abdominal muscles are in constant action, and com- 
municate to the stomach and bowels a healthy and agreeable stimulus ; and 
consequently, where the voice is raised and elocution rapid, as in many kinds 
of public speaking, the muscular effort comes to be even more fatiguing than 
the mental. When care is taken, however, not to carry reading aloud so far 
at one time as to excite the least sensation of soreness or fatigue in the chest, 
and it is duly repeated, it is extremely useful in developing and giving tone to 
the organs of respiration, and to the general system. To the invigorating 
effects of this kind of exercise, the celebrated Cuvier was in the habit of ascrib- 
ing his own exemption from consumption, to which, at the time of his appoint- 
ment to a professorship, it was believed he would otherwise have fallen a sacri- 
fice. The exercise of lecturing gradually strengthened his lungs and improved 
his health so much that he was never afterward threatened with any serious 
pulmonary disease. But, of course, this happy result followed because the 
exertion of lecturing was not too great for the then existing condition of his 
lungs. " — Combos Physiology. 

14. The production of the articulate sounds ? What experiment is mentioned 1 



THE VOICE. ' 279 

and simple, or, in other words, a whisper is produced. Still further 
continue the experiment, while permitting vocal sounds to be made, 
and there will bo produced a loud and whispering speech at the 
same moment ; thus showing that voice and speech are the result 
of two distinct acts. Sighing, in like manner, is produced in the 
mouth and throat ; if, however, a vocal sound be added, the sigh is 
changed into a groan. 

15. Ventriloquism is a peculiar modification of natural speech, 
rhich consists in so managing the voice that words and sounds ap- 
pear to issue, not from the person, but from some distant place, as 
from the chimney, the cellar, or the interior of a chest. The origi- 
nal meaning of the word ventriloquism (that is, speaking from the 
belly) indicates the early belief that this mode of speech was de- 
pendent upon the possession and use of some special organ besides 
the larynx and mouth ; but at the present time it is known that it 
is produced by these organs alone, and that the sources of deception 
consist, on the part of the performer, in the dexterous management 
of the voice, together with a talent for mimicry ; and, on the part 
of the auditory, in the liability of the sense of hearing to error in 
respect to the direction of sounds. The ventriloquist not only seems 
to " throw his voice," as it is said, or simulates the sound as it usu- 
ally appears at a distance with but little motion of the lips and face, 
but he imitates the voices of an infant and of a feeble old man, of 
a drunken man disputing with an exasperated wife, the broken lan- 
guage of a foreigner, the cry of an animal in distress, demonstrating 
that the performer must be proficient in the art of mimicry. Ven- 
triloquism was known to the ancient Eomans and Greeks ; and it is 
thought that the mysterious responses that were said to issue from 
the sacred trees and shrines of the oracles at Dodona and Delphi 
were really uttered by priests who had the power of producing this 
form of speech. {Read Notes 4 and 5.) 

4. Improvement of Conversation by Vocal Training. — " For 

years I had fallen into a low, drawling, lazy tone of voice in my ordinary con- 
versation ; my utterance came forth in a cloud, and had its dwelling there. 
From divers experiments and observations I had long ago assured myself that 



15. What is ventriloquism ? Indication of the original meaning of the word ? How are 
the ventriloquous sounds produced ? 



280 THE VOICE. 

this was a capital defect ; but this assurance had brought with it no reform. 
Now, at last, I attempted it in good earnest. I studied to bring myself out 
of my listlessness, to acquire a rapid, distinct, and articulate enunciation. No 
man can miss this acquisition unless from some organic infirmity, provided 
only that he pursue it steadily and earnestly. I employed a variety of exer- 
cises for the voice, as recitation, the frequent repetition of the same passage, 
slowly at first, and then more quickly, up to my highest pitch of rapidity, the 
pronunciation of foreign languages, Greek for the sake of fullness, and French 
for distinctness and despatch. As a result, I became comparatively a clear 
and satisfactory speaker; and as my talk was more distinct my thoughts were 
all the more pointed and precise. I acquired an evenness of tone, a confidence, 
a complacency ; my conversation, as the French say of their language, went of 
itself; I had leisure to look chiefly to my direction, to march on to my object" 
— Self- Formation, by Capel Lofft. 

5. Ventriloquism and Sound-Painting. — " Ventriloquism bears the 
same relation to other phenomena of sound that perspective does to optical 
phenomena. The art of perspective consists in portraying upon a flat surface 
the appearance of objects at a distance from it, so that the same effect shall ba 
produced upon the eye by the picture as would be produced by the objects 
themselves. In order to do this, the form, tints, and shades are reproduced, 
not as they really are, but as they are modified by position and distance. Or 
it may be said to consist in making and arranging a group of objects so that 
when viewed at a given distance they shall produce the same optical effect 
produced by another set of objects arranged in different positions and at dif- 
ferent distances. 

"Ventriloquism consists in making and arranging sounds so that when 
heard at a given distance they shall produce the same effect upon the ear that 
another set of sounds produce arranged in different positions and at different 
distances. 

" Sounds from a distance are of course weakened, and they also have another 
quality which may be compared to the indistinctness or outline in objects seen 
at a distance. In proportion as the fine ear of the ventriloquist can appreciate 
these modifications will be his success in imitating distant sounds. For as to 
see correctly is the first essential to success in drawing, so is hearing correctly 
the first essential in ventriloquism. 

"There are many sounds which cannot be imitated by voice merely, such 
as the singing of birds, the strident noise of a saw, the whistling of a plane, 
etc. Such and similar unmusical sounds are imitated by means of the teeth, 
the lips, or the soft parts of the mouth. Thus, the noise of a saw is like that 
produced by hawking, only much prolonged, and modified by the cheeks; 
singing of birds may be imitated by whistling through the teeth ; the foam- 
ing of soda-water by breathing with open lips into a tumbler, etc To per- 
sons having a fine ear this amusing art is not difficult, but we object to the 
name applied to it. It ought to be called sound-painting." 



THE VOICE. 281 



QUESTIONS FOR TOPICAL REVIEW. 

PAGE 

1. "What distinction is made between speech and voice 271 

2. What is said of each ? 271 

3. What does speech usually indicate? 272 

4. How is speech lelated to hearing? 272 

5. Name and describe the organ of the voice 273 

6. What other organs are concerned? 273 

7. What offices have the cartilages ? 273 

8. Explain and locate the epiglottis 274 

9. Say what you can of the vocal cords 274 

iO. State how a cold affects the voice 275 

11. What does the laryngoscope reveal to us ? 275 

12. Upon what does quality of voice depend ? 276 

13. What change takes place when the voice is raised ? 276 

14. How do the chest and trachea take part? 276 

15. How, the teeth, lips and tongue ? 277 

16. What are the varieties of voice ? 277 

17. What changes take place with age ? 277 

18. Mention the ordinary range of voice and instance an exception 277 

19. What further is said of speech ? 278 

20. What is ventriloquism? 279 

21. How produced? , 279 

22. What mysteries does it help to explain? 279 



CH1AJPTE3R XII. 

The Use of the Microscope in the Study of Physiology. 

1. The Law of the Tissues. — The will of an infinite Creator 
is obeyed by atoms as well as by worlds. He has seen fit to com- 
mit all the functions of life to structures or tissues so small as to be 
invisible to the naked eye. A muscle, for example, as we have al- 
ready learned, is composed of innumerable filaments, visible only by 
the aid of the microscope ; and the power of the muscular mass is 
but the sum of the contractile power of the filaments which enter 
into its composition. Again, each cell of the liver, invisible to un- 
assisted sight, is a secreting organ, and the liver performs as much 
duty as the sum of these minute organs renders possible. 

2. The Necessity of the Microscope. — If, therefore, we would 
know the real structure of the human body, we must make use of 
the microscope. Our eyes are constructed for the common offices of 
life, to provide for our wants and guard us from the ordinary sources 
of danger; but by arming them with lenses, the real structure of 
plants and animals is revealed to our intelligence ; and enemies, 
otherwise invisible, that lie in wait in the air we breathe, and in 
our daily food and drink, to destroy life, are guarded against. 

3. Convex Lenses, or magnifying glasses, are disks of glass or 
other transparent substances, which have the property of picturing 
upon the retina of the eye an image of an object larger than the 
image produced there without their aid. The glasses used in 
microscopes are either double convex lenses (a) or plano-convex 
lenses (b). If either of these lenses be placed over a hole in the 
shutter of a darkened room, or over the key-hole of a door, and a 
piece of paper be held at a proper distance, a picure of all objects in 

1. The will of the Creator, by what obeyed? The power of a muscle? Amount of duty 
performed by the liver ? 

2. Necessity for using the microscope ? The advantages gained by its use ? 

3. What are convex lenses ? Kind of lenses used in microscopes? Experiment? Picture 
thrown upon the eye ? Derivation of the word microscope ? 



THE MICROSCOPE. 283 

front of the lens will be thrown on the paper, as in the camera- 
obscura or the magic-lantern. !Nbw, in the same manner, a lens 
throws a picture of objects to which it is directed on the retina of 
a b 

| > 

▼ Fig. 69. W 

the eye, and when that picture is larger than the image made in the 
eye by the object without the aid of the lens, it is magnified, or the 
lens has served as a microscope, so called from its use in seeing 
small objects, from mikros, small, and skopeo, to see. 

4. Different Kinds of Microscopes. — Microscopes are either 
simple or compound. The glasses of magnifying spectacles, like 
those commonly used by aged persons, are simple microscopes. 
Magnifying glasses, mounted in frames, such as are for sale by 
opticians and others for the detection of counterfeit money, are 
simple microscopes, and are useful in studying the coarser structure 
of plants and animals. 

5. The most powerful simple microscopes are made by melting 
in a flame a thread of spun glass, so as to form a minute globule or 
bead, which, when set in a piece of metal and used to examine ob- 
jects on a plate of glass held up to the light, gives a high magnify- 
ing power. In practice, however, it is found better to use several 
magnifying glasses of moderate power than a simple lens alone of 
high power. A combination of two lenses is called a doublet — of 
three, a triplet. All simple microscopes throw an enlarged image 
of the object upon the retina. Compound microscopes are so con- 
structed that the enlarged image of an object is again magnified by 
a second lens, and hence their magnifying power is vastly superior 
to that of simple microscopes. 

6. The accompanying diagrams will explain the action of the 

4. Kinds of microscope ? What are simple microscopes ? 

5. Construction of the most powerful simple microscopes? In practice? A doublet? 
Triplet? Why are compound microscopes superior to simple ones? 

0. Explain, by means of the diagram, the action of the compound microscope. 



284 



THE MICROSCOPE. 



compound microscope compared with that of the simple microscope 
In Fig. 70, which represents the working of the simple microscope, 
the rays from the object (a b), passing through the lens (l), form an 
image (a! b') in the retina of the eye (e), and as all images are in* 
verted in the eye, the object is seen as all other objects are, and 
appears erect. In Fig. 71 is seen the action of the compound 
microscope. An inverted image (a! b') of the object (a b) is mag 
nified by the second lens (i/), and an erect image is thrown upon 




Fig. 70. -Simple Microscope. 

the retina, which, as all other objects seen erect with the naked eye 
are inverted, gives to the image a contrary direction, or inverts it to 
the mind. 

7. A Compound Microscope consists of two portions: the 
optical portion, or the lenses, and the mechanical portion, or the 
instrument which bears the lenses. The glasses of a compound 
microscope are two : the object-glass and the lower lens of Fig. 71, 
and the ocular or eye-piece and the upper piece of Fig. 71. Both the 
object-glass and the eye-piece may, and usually do, consist of more 
than one lens, for, as has been previously mentioned, better results 
are obtained by a combination of lenses of moderate power than 
by single lenses of high power and great curvature. 

8. How to Choose and Use a Microscope. — No attractiveness 
in the mechanical part of a microscope can compensate for inferior 
lenses ; and the very first consideration in the choice of an instru- 
ment should be the excellence of the optical part of the instrument. 
In the use of the instrument, care should be exercised to keep the 
lenses clean, free from dust, not to press the object-glass upon the 
object under observation, and not to wet it in the water in which 



7. Portions, in a compound microscope? The glasses? 

8. How to choose a microscooe ? How to use it? 



THE MICROSCOPE. 



285 



o e 



most objects are examined. A good microscope requires its own 
table ; and when not in use, should be covered by a bell glass, or 
a clean linen cloth. 

9. The mechanical portion of the instrument m 
varies greatly in different instruments. That 
one is the best which is the simplest, the most 
solid and most easily managed. Most objects in 
human anatomy are examined in water or in 
other liquids, or they are themselves liquids; 
hence an oblique stage is often inconvenient. 

10. Additional Apparatus. — As almost all 
objects in human anatomy are examined by 
transmitted light thrown up from the mirror 
beneath the stage through the object to the eye, 
they must be placed upon strips of clear glass 
about three inches long and one inch wide, com- 
monly called "slides." These should be pro- 
cured with the microscope. Again, most objects 
seen with high powers require to be covered 
with a thin plate of glass, very properly called 
a " cover," that the moisture of the specimen 
may not tarnish the object-glass. Square or cir- 
cular covers of very thin glass are therefore pro- 
vided; and a good supply of these should be 
always on hand. These glasses should be kept 
in a covered dish filled with a mixture of alco- 
hol and water. Simple water will not remove 
the fatty matter which exists in all animal tis- 
sues, and, therefore, the glasses cannot be thor- 
oughly cleaned with it alone. 

11. When glasses are required for use, 
they should be removed from the liquid and 
wiped clean and dry with a soft linen handker- 
chief. Delicate knives, scissors, needles mounted in handles, for. 
ceps, pipettes or little tubes for taking up water, should be ob- 

9. The characteristics of the best instrument? What special requisites should be 
insisted upon ? Why, as to a horizontal stage ? 

10. Slides? Covers, square and circular ? How kept? 

11. Cleaning the glasses ? Knives, scissors, etc. ? Various liquids ? 




Fig. 71. —Compound 
Microscope. 



286 THE MICROSCOPE. 

tained; these are essential to all microscopical study. The table 
should be supplied with . glass-stoppered bottles containing the 
various liquids ordinarily used in the study of physiology. Thus, 
tincture of iodine is indispensable in studying vegetable structure, 
acetic acid in the study of animal tissues ; and other articles will 
have to be added from time to time, as your progress in study 
demands them. 

12. Preliminary Studies. — In order to prepare the way for the 
study of any department of science with the aid of the microscope 
— for the microscope is but an eye, and can be turned in almost any 
direction for purposes of investigation — it is necessary to become 
acquainted with the many objects which are liable to complicate the 
examination of particular structures. Both air and water are full of 
floating bodies, and the most common of these should first occupy 
the attention. In the city, particles of starch are alway floating in 
the air. Take a very minute portion of wheat flour, place it in the 
middle of a clean glass " slide," drop upon it a drop of pure water, 
cover it with a plate of thin glass, and examine it with a power of 
from one hundred to six hundred diameters. It will be found to be 
composed of minute grains or granules, the largest of which are made 
up of coats or layers, like an onion, arranged around a central spot 
called the hilum. 

13. Make another preparation in the same manner, and, after 
adding the water and before covering with the thin glass cover, add 
a small drop of a solution of iodine. Now, upon examining the 
specimen, every grain will be seen to be of a beautiful deep blue 
color. After thus studying wheat starch, the starch of Indian corn, 
of arrow-root, and of various grains should be examined in like 
manner, and their resemblances and differences noted. The granules 
of potato-starch are as distinctly marked as any. 

14. Fibres of cotton, lint, and wool are liable to be found in every 
specimen prepared for microscopical examination. In order to study 
these, any cotton, woolen, or linen fabric, or garment, may be 
scraped, and the scrapings placed on a piece of glass moistened with 



12. Bodies, in air and water? The examination of starch? 

13. The examination with solution of iodine? Advice respecting other articles? 
\i. Directions for examining cotton and other fibres? Vegetable hairs ? 



THE MICROSCOPE. 287 

water, covered with the thin glass plate or cover as before, and ex- 
amined with the same magnifying power, namely, from one hundred 
to six hundred diameters. Vegetable hairs or down are constantly 
floating in air and water. These are of very various forms, 
are simple or grouped, and form very interesting objects of study. 
They are readily procured from the epidermis or outer mem- 
brane of the leaves or stems of plants, by cutting with a delicate 
knife. 

15. The tissues of plants, epidermis, ducts, and woody fibres are 
constantly found in microscopic preparations. They may be studied 
in delicate sections made with a sharp knife, or by tearing vegetable 
tissues apart with needles. The down of moths, the hairs of 
different animals, the fibres of paper, the most common animalcules 
in water, the dust of shelves, and generally the structures found in 
all vegetable and animal substances by which we are surrounded, 
should be studied as a preliminary to any special line of micro- 
scopical investigation. 

16. The Study of Human Tissues. — When this has been done 
and familiarity with the use of the instrument has been obtained, 
proceed to the study of the human body, for human physiology is 
our subject. If the end of the finger be pricked with a pin, a drop 
of blood may be procured for examination. Place this on one of the 
glass slides, cover it with a thin piece of glass, press down the cover 
so as to make a thin layer, and then examine with the magnifying 
power just mentioned. Do not add water, for that will cause the 
blood corpuscles to disappear. If the drop of blood is placed under 
the microscopa at once after being drawn from the finger, most in- 
teresting phenomena will be observed. The red corpuscles will be 
seen to arrange themselves in rows, like piles of coin, while 
the blood is coagulating. The spherical, white corpuscles will be 
left out of the rows of red disks, and, if the highest power be used, 
will be seen to change their shape constantly. 

17. If you scrape with a dull knife the inside of the cheek, the 
flattened scales of " pavement epithelium," or of the insensible cov- 



15. "Directions for examining various tissues ? Down of moths and other structures ? 

16. Directions for examining a drop of blood ? 

XI. Examination of the scales of the mouth ? Dandruff? 



288 THE MICROSCOPE. 

ering which, analogous to the scarf-skin on the outer surface of the 
body, lines the cavities of its interior, may be readily studied. 
They have the appearance of transparent tiles, each enclosing a 
round or oval body, called its nucleus. Dandruff and the scrapings 
from the skin of the body are composed of scales like those of the 
mouth, but they differ somewhat in being hardened by horny 
matter, and in having a very faint central body or nucleus. 

18. The Tissues of the Inferior Arimals. — The warm-blooded 
animals do not differ in the tissues or microscopic structures that com- 
pose them, but only in the amount and arrangement of these tissues. 
Milne-Edwards says these tissues " do not differ much in different 
animals, but their mode of association varies, and it is chiefly by 
reason of the differences in the combination of these associations in 
various degrees, that each species possesses the anatomical properties 
and characters which are peculiar to it." 

19. Hence the butcher's stall will furnish all the materials for the 
study of the microscopic tissues. The structure of the heart, lungs, 
liver, brain, and muscle, may all be studied, and well studied, by 
using minute pieces of the flesh of the lower animals, especially of 
the quadrupeds. Such portions of these animals as are not exposed 
for sale can be readily obtained by order from the slaughter-house. 
To examine with the powers of which we have been speaking, it is 
only necessary to cut off exceedingly small pieces, tear them apart 
with needles, or make very delicate sections with a sharp knife. 

20. Incentives to Study. — A complete knowledge of all minute 
structures is not to be expected at once, for you are here introduced 
into a new realm of Nature, a world of little things as vast, as won- 
derful, and as carefully constructed as the starry flrmanent — that 
other realm of grand objects which the astronomer nightly scans 
with the telescope. It will not appear singular, therefore, if, at 
first, you feel strange and awkward in this new creation. With a 
little perseverance, however, and with the attention directed toward 
simple objects at the outset, it will not be long before an increasing 
experience will engender confidence. 

21. If to all this there be added an enthusiastic study of the 

18. In what, as respects the tissues, do the warm-blooded animals differ? Statement of 
Milne-Edwards ? 

19. How to procure materials for the study of the tissues of man? 



> 



THE MICROSCOPE. 

standard authorities on the subject, the rate of progress will be 
much more rapid. As compared with similar studies, few possess 
more interest than microscopy, and to the one who pursues it with 
fondness, it constantly affords sources of pleasure and agreeable sur- 
prises ; and in the end often leads to new and valuable additions 
to the sum of huma& knowledge. The depths which the micro- 
scope is employed to fathom are no more completely known than 
are the heights above us explored and comprehended by the 
astronomer. 



QUESTIONS FOR TOPICAL REVIEW. 

PAGE 

I? Say what you can of the law of the tissues , 282 

2. Whati then, is the necessity of the microscope ? 282 

£. Define and state use of convex lenses 283 

4. Name some of the kinds of microscopes .„ 283 

& Explain action of compound microscope 283 

6. Of what parts does it consist ? 284 

7. What parts are of most importance ? 284 

8. How would yon prepare specimens ?. 285 

9. What further directions are given ? 285,235 

10. What is said of preliminary studies?. ,, 286 

U. Give statement regarding study of human tissues .., 2&7 

12 Tissues of inferior animals ,«... -......,.. Sfe8 






APPENDIX. 



Poisons and their Antidotes. 

Accidents from poisoning are of such frequent occurrence, that every one 
should be able to administer the more common antidotes, until the services qf 
a physician can be obtained. As many poisons bear a close resemblance to 
articles in common use, no dangerous substance should be brought into the 
household without having the word poison plainly written or printed on the 
label ; and any package, box, or vial, without a label, should be at once 
destroyed, if the contents are not positively known. 

When a healthy person is taken severely and suddenly ill soon after sovu 
substance has been swallowed, we may suspect that he has been poisoned. In 
all cases where poison has been taken into the stomach, it should be quickly 
and thoroughly expelled by some active emetic, which can be speedily ob- 
tained. This may be accomplished by drinking a tumblerful of warm water, 
containing either a tablespoonful of powdered mustard or of common salt, or 
two teaspoonfuls of powdered alum in two tablespoonfuls of syrup. When 
vomiting has already taken place, it should be continued by copious draughts 
of warm water or mucilaginous drinks, such as gum- water or flaxseed tea. and 
tickling the throat with the finger until there is reason to believe that all of 
the poisonous substance has been expelled from the stomach. 

The following list embraces only the more common poisons, together with 
such antidotes as are usually at hand, to be used until the physician arrives. 

Poisons. 

Acids. — Hydrochloric acid; muriatic acid (spirits of salt); nitric acid (aqua 
fortis); sulphuric acid (oil of vitriol). 

Antidote. — An antidote should be given at once to neutralize the acid. 
Strong soapsuds is an efficient remedy, and can always be obtained. It should 
be followed by copious draughts of warm water or flaxseed tea. Chalk, mag- 
nesia, soda, or saleratus (with water), or lime-water, are the best remedies. 
When sulphuric acid has been taken, water should be given sparingly, because, 
when water unites with this acid, intense heat is produced. 

Oxalic acid. 

Antidote. — Oxalic acid resembles Epsom salts in appearance, and may 



APPENDIX. 291 

sily be mistaken for it. The antidotes are magnesia, or chalk mixed with 
water. 

Prussic Acid; oil of bitter almonds; laurel water; cyanide of potassium 
(used in electrotyping). 

Antidote. — Cold douche to the spine. Chlorine water, or water of 
ammonia largely diluted, should be given, and the vapor arising from them 
may be inhaled. 

Alkalies and their Salts. — Ammonia (hartshorn), liquor or water of am- 
monia. Potassa : — caustic potash, strong lye, carbonate of potaxsa (pearlash), 
nitrate of potassa (saltpetre). 

Antidote. — Give the vegetable acids diluted, as weak vinegar, acetic, citric, 
or tartaric acids dissolved in water. Castor oil, linseed oil, and sweet oil may 
also be used ; they form soaps when mixed with the free alkalies, which they 
thus render harmless. The poisonous effects of saltpetre must be counteracted 
by taking mucilaginous drinks freely, so as to produce vomiting. 

Alcohol. — Brandy, wine; all spirituous liquors. 

Antidote. — Give as an emetic ground mustard or tartar emetic. If the pa- 
tient cannot swallow, introduce a stomach pump ; pour cold water on the head. 

Gases. — Chlorine, carbonic acid gas, carbonic oxide, fumes of burning char- 
coal, sul})huretted hydrogen, illuminating or coal-gas. 

Antidote. — For poisoning by chlorine, inhale, cautiously, ammonia (harts- 
horn). For the other gases, cold water should be poured upon the head, and 
stimulants cautiously administered; artificial respiration. (See Marshall 
Hall's Ready Method, page 293. ) 

Metals. — Antimony, tartar emetic, wine of antimony, etc. 

Antidote. — If vomiting has not occurred, it should be produced by tickling 
the throat with the finger or a feather, and the abundant use of warm water. 
Astringent infusions, such as common tea, oak bark, and solution of tannin, 
act as antidotes. 

Arsenic. — White arsenic, Fowler's solution, fly-powder, cobalt, Tar is green, 
etc. - ______^ 

Antidote. — Produce vomiting at once with a tablespoonful or two of pow- 
dered mustard in a glass of warm water, or with ipecac. The antidote is hy- 
drated peroxide of iron. If Fowler's solution has been taken, lime-water must 
be given. 

Copper. — Acetate of copper (verdigris), sulphate of copper (blue vitriol), food 
cooked in dirty copper vessels, or pickles made green by copper. 

Antidote. — Milk or white of eggs, with mucilaginous drinks (flaxseed tea, 
etc. ), should be freely given. 

Iron. — Sulphate of iron (copperas), etc. 

Antidote. — Carbonate of soda in some mucilaginous drink, or in water, is 
an excellent antidote. 

Lead. — Acetate of lead (sugar of lead), carbonate of lead, (white lead), water 
kept in leaden pipes or vessels, food cooked in vessels glazed with lead. 



292 APPENDIX. 

Antidote. — Induce vomiting with ground mustard or common salt in warm 
water. Tbe antidote for soluble preparations of lead is Epsom salts; for the 
insoluble forms, sulphuric acid largely diluted. 

Mercury. — Bi-chloride of mercury (corrosive sublimate), ammoniated mer- 
cury (white precipitate), red oxide of mercury (red precipitate), red sulphuret 
of mercury (vermillion). 

Antidote. — The white of eggs, or wheat flour beaten up with water and 
milk, are the best antidotes. 

Silver. — Nitrate of silver (lunar caustic). 

Antidote. — Give a teaspoonful of common salt in a tumbler of water. It 
decomposes the salts of silver and destroys their activity. 

Zinc. — Sulphate of zinc, etc. (white vitriol). 

Antidote. — The vomiting may be relieved by copious draughts of warm 
water. The antidote is carbonate of soda administered in water. 

Narcotic Poisons. — Opium (laudanum, paregoric, salts of morphia, God- 
frey's cordial, Dalby's carminative, soothing syrup, cholera mixtures), aconite, 
belladonna, hemlock, stramonium, digitalis, tobacco, hyosciamus, nux vomica, 
strychnine. 

Antidote. — Evacuate the stomach by the most active emetics, as mustard, 
alum, or sulphate of zinc. The patient should be kept in motion, and cold 
water dashed on the head and shoulders. Strong coffee must be given. The 
physician will use the stomach pump and electricity. In poisoning by nux 
vomica or strychnine, etc. , chloroform or ether should be inhaled to quiet the 
spasms. 

Irritant Vegetable Poisons. — Croton oil, oil of savinc, poke, oil of tansy, 
etc. 

Antidote. — If vomiting has taken place, it may be rendered easier by 
copious draughts of warm water. But if symptoms of insensibility have come 
on without vomiting, it ought to be immediately excited by ground mustard 
mixed with warm water, or some other active emetic, and after its oper- 
ation an active purgative should be given. After evacuating as much of the 
poison as possible, strong coffee or vinegar and water may be given with ad- 
vantage. 

Poisonous Fish. — Conger eel, mussels, crabs, etc. 

Antidote. — Evacuate, as soon as possible, the contents of the stomach and 
bowels by emetics (ground mustard mixed with warm water or powdered alum), 
and castor oil, drinking freely at the same time of vinegar and water. Ether, 
with a few drops of laudanum mixed with sugar and water, may afterward be 
taken freely. 

Poisonous Serpents. — Antidote. — A ligature or handkerchief should be 
applied moderately tight above the bite, and a cupping-glass over the wound. 
The patient should drink freely of alcoholic stimulants containing a small 
quantity of ammonia. The physician may inject ammonia into the veins. 

Poisonous Insects. — Stings of scorpion, hornet, wasp, bee, etc. 



APPENDIX. 293 

Antidote. — A piece of rag moistened with a solution of carbolic acid may 
be kept on the affected part until the pain is relieved ; and a few drops of car- 
bolic acid may be given frequently in a little water. The sting may be 
removed by making strong pressure around it with the barrel of a small watch- 
key. 

Drowning". 

Marshall Hall's "Ready Method" of treatment in asphyxia fron 
drowning, chloroform, coal-gas, etc. 

1st. Treat the patient instantly on the spot, in the open air, freely exposing 
the face, neck, and chest to the breeze, except in severe weathei. 

2d. In order to clear the throat, place the patient gently on the face, with 
one wrist under the forehead, that all fluid, and the tongue itself, may fall for- 
ward, and leave the entrance into the windpipe free. 

3d. To excite respiration, turn the patient slightly on his side, and apply 
some irritating or stimulating agent to the nostrils, as veratrine, dilute am- 
monia, etc. 

4th. Make the face warm by brisk friction ; then dash cold water upon it. 

5th. If not successful, lose no time ; but, to imitate respiration, place the 
patient on his face, and turn the body gently, but completely on the side, and 
a little beyond; then again on the face, and so on, alternately. Repeat these 
movements deliberately and perse veringly, fifteen times only in a minute. 
("When the patient lies on the thorax, this cavity is compressed by the weight 
of the body, and expiration takes place. When he is turned on the side, this 
pressure is removed, and aspiration occurs. ) 

6th. When the prone position is resumed, make a uniform and efficient 
pressure along the spine, removing the pressure immediately, before rotation on 
the side. (The pressure augments the expiration, the rotation commences in- 
spiration. ) Continue these measures. 

7th. Rub the limbs upward, with firm pressure and with energy. (The ob- 
ject being to aid the return of venous blood to the heart ) 

8th. Substitute for the patient's wet clothing, if possible, such other cover- 
ing as can be instantly procured, each bystander supplying a coat or cloak, 
etc. Meantime, and from time to time, to excite inspiration, let the surface of 
the body be slapped briskly with the hand. 

9th. Rub the body briskly until it is dry and warm, then dash cold water 
upon it, and repeat the nibbing. 

Avoid the immediate removal of the patient, as it involves a dangerous loss 
of time; also, the use of bellows, or any forcing instrument ; also, the warm 
bath, and all rough treatment. 

The Care of the Sick-Room. 

The sick-room should be bright and airy, and "Sweetness and light" its 
motto. Other things being equal, it is best on one of the upper floors — in the 



f?94 APPENDIX. 

case of some "catching " disease on the top floor. Let it be on the sunny side 
of the house. If for any reason the light of the sun is temporarily to be 
avoided— as when the eyes are sensitive or have been operated upon — let the 
light be shut out by a proper arrangement of blinds or curtains. The air- 
supply to be breathed by the sick person should be pure. Those who, in health, 
find themselves in an impure air can quit it ; they are not compelled to suffer 
from it ; but a sick person may be incapable of recognizing the bad quality of 
the air, as well as helpless to free himself from it. 

To keep the air pure, the windows should be opened as often as three times 
a day, care being taken to protect the patient from being chilled, while the 
room is being aired. 

Unless the physician shall direct differently, one window — that most remote 
from the bed — should be open an inch or more both day and night, and in all 
seasons. The extent to which the sash shall be lowered must be governed 
largely by the weather and the direction of the wind. 

A fire, in an open fireplace, except in summer weather, will be a great help 
towards keeping the air pure. The upward current through a chimney-flue, if 
unobstructed, is equal to or not far below 20, 000 cubic feet per hour ; an outlet 
sufficient fo* a room occupied by ten persons. 

The inlet of air, however, must not be forgotten, otherwise the air of the 
room tends to become both impure and too thin. As our houses are generally 
constructed, the inlet of air is best secured by a window-sash being lowered 
from the top. 

Take special care that no stationary wash-basin or other sewer-connected con- 
venience is improperly plumbed, and that sewer gas cannot by any possibility 
escape into the sick-room. 

The swinging of doors to create a current is not an efficient means of ven- 
tilation, as it agitates the air of the room without purifying it, and often dis- 
turbs the patient. 

A draught of air is to be avoided ; it will seldom occur that the air of the 
room requires to be so speedily changed that the patient need be exposed to a 
draught ; never, when care has been taken to provide continuous and gradual 
ventilation. 

It should be borne in mind that cold air is not necessarily pure air, and that 
rentilation is not less needed in winter than in warm weather. 

Sleep is a great necessity to the sick. If a well person slumbers in the day- 
time, it will interfere with his sound repose at night, but with the sick this is 
generally not the case. The more they sleep the more favorable are the 
chances for their recovery : so that it will be readily seen how important it 
is to avoid noise and jar in the sick-room, especially if the disease is 
acute. 

Bear in mind that even slight noises, as the rustling of garments, the creak- 
ing of doors, whispering, or noisy footfalls, may be sufficient to disturb a brain 
that is rendered sensitive by pain or wakefulness. 



APPENDIX. 295 

The clothing next the skin should be changed more frequently in sickness 
than in health. These changes must be quickly and deftly made, and with as 
little disturbance as possible. 

Under some conditions of disease, the best welfare of the patient is accom- 
plished by having two beds in the room instead of one. 

The temperature of the room must be watched. To that end a thermometer 
should always be present, and easily approached. It is better not to have it 
directly in the view of the patient. The temperature should not be allowed to 
vary much from 65° F., unless the doctor otherwise directs. 

Let the furniture be as plain and as free from upholstery as possible ; not 
many pieces are required. Movable carpets or rugs are better than those that 
are permanently laid. Curtains about the windows are out of place in a sick- 
room : so are flowering plants and birds, as a general rule. Florence Night- 
ingale, however, makes an exception in the case of chronic invalids, and 
consents to the comforting influence of a pet bird or two. 

In regard to the admission of visitors and conversation, much will depend 
upon the strength of the patient and the kind of sickness : at many times these 
are to be forbidden, as having a disquieting influence. When contagious 
disease is in the house, the sick-room must be avoided by all except those 
who have the care of the patient, and those having this care should avoid 
coming in contact with the other members of the household, especially the 
children. 

Bear in mind that everything brought in contact with the sick is liable to 
endanger the health of the well. 

No articles in use by the invalid should be removed or used by others until 
thoroughly disinfected ; the dishes and spoons should be put in boiling water 
before being taken from the room. The room itself should be fumigated with 
sulphur when the person is removed from it. 

Old pieces of muslin, etc., may be used instead of handkerchiefs to receive 
the poisonous discharges from the nose, mouth, and throat. These can be 
destroyed by fire, and thus prevent the danger of conveying the disease to 
others. 

"Taking the breath " and kissing should be avoided by those in attendance 
upon the case. 

The bottles of medicine and other reminders of illness should, as far as con- 
venient, be withdrawn from the vdew of the sick. 

Such as are to be kept always at hand, should be arranged in an orderly 
way upon a tidily-covered bed-side table. The sight of a siphon bottle of 
aerated water is agreeable to most patients ; that maj r be kept in the room, 
but the vessels containing milk, drinking-water, etc., should be kept else- 
where. 

Disinfection. 

Filth fosters or produces certain diseases ; it should, therefore, be removed 
as soon as possible. When it is difficult to remove it, disinfectants come into 



296 APPENDIX. 

play, as they have the power to rob it of some of its disease-making force. 
But let it be remembered that disinfection is not cure ; it is not a substitute 
for cleanliness and pure air. The true cure is the removal of filth ; and when 
our homes are concerned in some question of drainage where the filth is out of 
our sight, it may be necessary to consult and employ the plumber or some 
other artisan. 

In times gone by, it was the custom to mask bad smells by burning pastiles, 
coffee, cascarilla, and the like. These are not now much used, for most per- 
sons have come to understand that the fumes thus created do not remove, but 
simply overpower the evil odors. 

Chemistry has advanced to such a point that various pungent chemical sub- 
stances, formerly not well known, can be furnished at small cost, and these 
substances have the power, in varying degrees, to check vile odors. Carbolic 
acid, chloride of lime, and Labarraque's solution are among the best known of 
these, but there are also certain of the salts of iron, and zinc, and the perman- 
ganate of potash that may be used. Sulphur is much used for the fumigation 
of rooms that have been infected. 

Another cheap disinfectant is a solution of chloride of lead. It is inodorous, 
effective, and the cost is small. Take half a drachm of the nitrate and dissolve 
it in a pint or more of boiling water. Dissolve two drachms of common salt 
in a pail or bucket of water ; pour the two solutions together, and allow the 
sediment to sink. A cloth dipped in this solution, and hung up in a room, 
will correct a bad odor promptly, or if the solution be thrown down a drain, 
or upon foul-smelling refuse, it will have the same effect. 

The room to be purified with sulphur should be made as tight as possible, 
so that no fumes can escape, either by window, door, or chimney. Put three 
pounds of sulphur in an iron pot, which should not stand upon woodwork or 
carpet, lest they be burned, but in a large pan of ashes, or upon a layer of 
bricks ; on this sulphur pour a tablespoonful of alcohol. This is then set on 
fire, and everybody immediately withdraws from the room. The room should 
remain closed ten hours, after which it should be thoroughly aired before it is 
occupied, for the fumes of the sulphur are irritating to the lungs. 

The chemicals above mentioned should be known and labeled as poisons. 
Many persons have been injured, if not killed, by incautiously or ignorantly 
drinking those that are of a liquid form. 

Heat is one of the best, if not the best disinfecting agent Articles of bed- 
ding and furniture that cannot well be treated otherwise, can be purified by a 
long exposure to a temperature of 240° F. In some cities, especially in Eng- 
land, furnaces are made for the reception of bulky articles that have become 
infected. 

Fresh pure air is another powerful agent. If woven fabrics, clothing, and 
the like are for a long time aired out of doors, they cease to be infective ; 
probably by the enormous dilution, if not destruction, of the elements of 
danger. 



APPENDIX. 297 

Certain diseases are " catching ;" they have the power of spreading from one 
person to another, chiefly by the particles that pass off from the body of the 
patient. Among these diseases are small-pox, measles, scarlet-fever, and diph- 
theria. Ihe articles that are worn or used by the patient become " infected," 
and they should be disinfected before they are used by others. As a rule, of 
course, a doctor will be called in to attend to these diseases. When that is so, 
follow his directions as to disinfection, as well as every other part of the treat- 
ment of the case. For substances that are not injured by being washed, a 
good and cheap disinfectant is sulphate of zinc ("white vitriol") and common 
salt dissolved in water, boiling hot if possible, using eight tablespoonfuls of 
the zinc and four of salt to the gallon of water. This is useful for clothing, 
bed-linen, towels, handkerchiefs, etc. After these articles have lain for an 
hour or two in this solution, they should be allowed to stand in boiling water 
before being washed. Infected articles that are of little value should, of 
course, be destroyed by fire. 

The United States Treasury Department has published the following formula 
for the disinfection of the rags coming from Egypt : "1. Boiling in water for 
two hours under a pressure of fifty pounds per square inch ; 2. Boiling in 
water for four hours without pressure ; or, 3. Subjection to the action of sul- 
phur fumes for six hours, burning one and one-half to two pounds of roll-brim- 
stone in each 1,000 cubic feet of space, with the rags well scattered upon 
racks." Either of these three methods is accepted as sufficiently thorough to 
prevent the spreading of cholera by means of rags. 



Emergencies. 

" The readiness is all."— Hamlet. 

The life of many a child has been saved by the fire-drill in schools, and 
great good has been done on shipboard by a drilling of the crews. 

If in a building filled with smoke, get down on hands and knees and crawl 
to door or window. 

In a cellar, well, or vat, where carbonic acid can collect, the true posture is 
to stand erect. If a candle, on being lowered into a suspected place, is put 
Dut, you may know that there is danger to human life. 

Burns and Scalds. — The secret of the best treatment of these injuries is to 
exclude the air from the wounded surfaces. When they are slight, and the 
skin is not destroyed but merely blistered, prevent the displacement of the 
skin as much as possible. Let the blisters be punctured, if necessary, to let 
out the liquid, and then keep the skin in place by cotton cloth or lint, wet 
with a solution of one teaspoonful of carbolic acid in a quart of water, or a 
strong solution of baking soda. The cloth should be kept wet constantly, but 
do not irritate the wound by taking ofF the dressing too often. 

Extensive burns are much worse than deep burns. In the former ease, the 



298 APPENDIX. 

outlook is grave, and the patient will probably require the best aid, both 
medical and surgical, of some physician. 

Scars after Burns.— If a burn be on the face, neck, or near a joint, it is 
not well to hasten the healing process, on account of the contraction that 
always takes place as the scar is formed. 

" Fire is a source of danger, and is very destructive to life at times. Spon- 
taneous combustion of the human body when saturated with alcohol is a myth, 
though perhaps the alcoholized body does burn more readily than one free 
from inflammable fluid. "When a lady is on fire, she should not, and ought 
not to be permitted to run ; that fans the flames amazingly. She must be 
laid down and rolled up in the nearest woolen article, — rug, coat or blanket. 
Such wrapping up in a non-inflammable article is a most effective method of 
extinguishing the flames. Immersion in water is, unfortunately, rarely prac- 
ticable. " — Fothergilh 

Illuminating Gas is dangerous in two ways. If it escapes into a tightly- 
closed room in sufficient quantities, it causes the death of the inmates by suffo- 
cation, unless some one from without discovers the perilous situation. If not 
too late, remove the patient into fresh air, undo the clothing, dash cold water 
on the face and neck, and employ artificial respiration, as in drowning (see 
p. 293). Again : If it escapes freely into an apartment, it forms an explosive 
compound by mixing with the air. If then a light is unguardedly taken into 
the place, an explosion that may be destructive to life will result. Always thor- 
oughly air any room that has the odor of escaping gas before a light is taken in. 

Kerosene is the cause of even more "accidents " than gas. Too much care 
cannot be taken in its use. Buy only that which has been tested, but remem- 
ber that not all that are marked as "safe" are truly so. If a responsible oil- 
man certifies that the oil will not "flash" under 140 degrees, it may be 
regarded as safe if properly used. Lamps should be filled only in the daytime. 
Never attempt to fill a lamp that is lighted, and never put kerosene in the 
stove for the purpose of kindling a fire. Yery small lamps are dangerous, as 
also is a lamp that has burned a long time, and has but very little oil in it. 

Frost-bites. — Keep away from the fire and in a cool room. Rub the nose 
or other part that has been " bitten " with snow or ice- water until the blood 
again is warmed and circulating in the part. Chilblains should not be brought 
to the fire ; if the skin is unbroken, it should be hardened by brushing it over 
with alcohol having tannin in it 

Cuts. — These, if severe, should be promptly attended by a physician, but 
everv one should know how to treat small wounds. Learn the difference 
between the two kinds of bleeding, called " arterial " and " venous." Arterial 
is bright red and comes in jets (or with throbs corresponding to the pulse) ; 
venous is dark-colored and flows continuously. In the former, press on that 
side of the wound nearer to the heart ; in the latter, on the further side. Or, 
pressure may be made over the wound itself with the fingers ; this may stop 
the loss of blood from small arteries as well as from veins. Loss of blood from 



APPENDIX. 299 

arteries is apt to be more rapid and dangerous than that from veins, and when 
the cut vessel is a large one, the skill of the surgeon will ordinarily be required 
in order to close the bleeding arteiy permanently and securely. 

It is well, in every household, to have, in some handy and well-known 
place, some strips of old muslin and some lint, or oakum, a bandage or two 
and some adhesive plaster, a soft sponge, and needles and thread in a basket 
or box by themselves. In this way, valuable time may be saved in the 
staunching of blood, flowing in consequence of some accidental cut or other 
injury. 

Fits or Convulsions. — These may be trivial or grave. If it is a young 
*voman, the attack is probably hysterical and, as a rule, not dangerous, and a 
sprinkle of cold water will bring relief. If the patient struggles with regular- 
ity of movement, and there is bloody froth on the lips, it is a case of epilepsy, 
and requires a physician's attendance. Meanwhile, protect the head from 
injury by putting a pillow or some soft article beneath it; a cork intro- 
duced between the teeth will prevent the biting of the tongue. Prevent the 
person from falling or injuring himself, but do not attempt to forcibly hold 
him quiet. 

In children, apply cloths dipped in water to the head; disturb the 
child as little as possible; do not use a warm bath until directed by the 
doctor. 

Fainting. — This occurs when the blood is deficient in the brain. The proper 
position, therefore, is upon the back. Let the window be opened to admit 
fresh air ; fanning, and the sprinkling of water are useful. If the clothing about 
the chest is tight, let it be loosened. If the faint occurs at church or some 
public gathering, remove the person promptly to the outer air ; for foul air is 
frequently the cause of the trouble. 

Vertigo. — This is "a rush of blood to the brain." The body should be 
placed in a sitting posture, with the head erect. If the blood escapes into the 
brain by reason of the rupture of a blood-vessel within it, the case is very 
grave, and the physician should be summoned at once. Meanwhile, let the 
position of the body be as above stated. Apoplexy is known, in very many 
cases, by the helpless condition of an arm or leg, or both. 

Sunstroke is seldom produced in this climate in persons who have not 
labored too hard. Fatigue and sun-heat are commonly the joint causes of 
sudden prostration in summer ; although ' ' heat-stroke " may occur in an 
artificially-heated atmosphere, without exposure to the sun. In the tropics, the 
least possible exertion is by the natives put forth during the midday hours. On 
very hot days, therefore, avoid fatigue and labor in the open air as much as 
possible. Keep the head cool. If any unusual, dizzy feeling comes on, apply 
cold water to the head and neck. If a person falls unconscious, and the skin 
is decidedly hot and dry, he should be taken to a cool place. If the face and 
head are red and hot, apply ice-water on cloths. *If pale, give stimulants 
gradually, and use cold water sparingly. 



300 APPENDIX. 

Shock may be caused by a fall or a blow upon the bead or the pit of tbe 
stomacb. It is known by slowing of tbe pulse and respiration; tbe face 
is pale and tbe skin becomes cool. Tbe bead should be placed low, some 
ammonia in water be given, and warmth applied to tbe surface of the 
body. 

The Home and Health. 

The location of the house should be airy, dry, and sunny. 

A certain amount of elevation is necessary, in order to secure proper drain- 
age. Too much shade must not fall upon the house, as sunlight is very 
necessary to a proper degree of animal vigor. Young children, as is well known, 
especially profit by the tonic influence of sunlight. 

The cellar is an important part of the dwelling ; therefore, unless care be 
taken for its ample ventilation, it will be the source from which is supplied 
much of the air breathed in the upper chambers of the house. If tbe cellar 
is damp the house is liable to become so, and if vegetables are stored in the 
cellar, an especial degree of care is needed to ventilate it thoroughly and 
constantly. 

House Drainage. — An English writer has stated that "the most im- 
portant part of tbe house is the drains." This, no doubt, sounds strangely to 
the ears of many, who have been brought up to view the parlor or drawing- 
room as the true centre of the house, and yet it is no foolish saying, when we 
reflect that with a bad system of drainage to a house every dweller therein 
stands in peril of several forms of disease that, mild as the cases may be, are 
a source of anxiety, and when severe, too often have a fatal termination. 
Drain-diseases, such as typhoid fever, dysentery, diphtheria, and scarlet fever, 
often destroy entire families. These diseases do not always spring upon a home 
through defective drainage, but. Avhen they do, they frequently show them- 
selves in a very violent form. 

Drainage (as applied to dwellings) consists in conveying away from the house 
the liquid and solid impurities that would otherwise accumulate in or near the 
dwelling. Waste is a necessary accompaniment of all animal life, to the prepa- 
ration and the taking of food, to the clothing of the body, to bathing and other 
simple acts of daily life. The waste material of houses tends to decay and to 
become offensive. It must, therefore, not only be put out of sight and smell, 
but must be removed so far away that it cannot return in the form of danger- 
ous, invisible gases of decomposition. 

The best house-drains are made of iron or glazed earthenware, carefully 
selected and well laid. The joints of the pipes should be gas-tight. The soil- 
pipe should be carried up to and through the roof. All the waste-pipes from 
basins, etc., in the rooms should be joined in a gas-tight manner to the soil- 
pipe, and each and every basin and other fixture should have a separate trap. 
What is a trap ? It is a device that is designed to retain a certain portion of 



APPENDIX. 301 

the water running through it — called the "water-seal" — so that the ascent of 
air or gas, from the drain back into the room, is prevented. It " traps" the 
sewer gas away from us. Whenever a fixture has been used and there is not, 
beyond all doubt, a sufficiency of water to fill the trap, additional water should 
be poured in. Traps are of various sizes, and of an infinite variety of patterns 
and patents, and must vary greatly according -to their situation ; but one thing 
should be made sure of in their use — namely, that they hold not less than two 
inches of water asa " seaL" 

There is at almost all seasons of the year an upward, because warmer, cur- 
rent of air through the main pipes. It is therefore better to have a fresh-air 
inlet pipe near the point where the drain leaves the house-wall. This helps 
to prevent the unsealing of traps. It also brings about a purer condition of 
the air in the interior of the system of pipes — so useful is this air-current 
through the soil-pipe that if applied there is little danger of the escape of 
sewer gas into the living rooms. 

What is sewer gas or sewer air ? It varies greatly in different places and at 
different times. It is not a definite gas, like oxygen, nitrogen, etc. , but varies 
in composition, and what is still more worthy of note, it varies in its 
dangerous qualities. It is not always offensive, although it is generally so ; 
its odor has been described as being "sweetish and sickish." Its danger- 
ous qualities have not yet been determined by chemistry or the microscope, 
but one practical point may be borne in mind — namely, that when a case or 
cases of contagious disease occur in any house along any given line of sewer 
pipes, it is best to use disinfectants in the drainage of the other dwellings 
along the same line of sewer. Children should avoid playing over or around 
the sewer-gratings in the streets at all times, and especially when scarlet fever 
and like contagious diseases are known to be in the neighborhood ; for the exit 
of sewer air at these points is always very free, unless it be directly after rainfall. 

One other point must be remembered — that the best-laid system of house- 
plumbing is not indestructible. In the course of time, defects will arise, 
breaks will occur ; for this reason it would be well for every householder to 
have an examination made at intervals of every joint and along the whole line 
of the house connection with the sewer or drain. 

It is thought by many that sewer gas is not found in the country because 
there are no sewers — they have been misled by the word. If the words "drain 
air" or "filth gas" had been adopted, the universal production of this inju- 
rious substance, in close connection with every abode of man, wherever 
located, might have been better understood. In country houses there are, 
perhaps, fewer dangers of contamination of the air we breathe by waste 
products, because there are fewer water-closets, wash-basins, sinks, etc., and 
the rooms are less exposed to impure air. 

But in the country danger is apt to come by or through the pollution of the 
water supply. The well, which furnishes that cool and refreshing draught, is 
the point to be watched. It is convenient to have the well near the hous«, 



302 APPENDIX. 

because when snow is on the ground and the weather is cold, the distance to 
the well from the house is a matter of no small moment. Near the house 
must be the stable and pens for animals — the waste from the house goes upon 
the ground, and not very far away from the house — the chamber slops and the 
more offensive matters go into a pit, which must not be too distant. The 
result of all these conditions is a pollution of the soil at all these points — a 
pollution which spreads with every rainfall, and which, sooner or later, 
reaches the well ; yet the water may appear as pure as ever. It only remains 
to have the suitable disease-germ lodged in this polluted territory to bring 
down the whole household with a fever. This is the kind of soil-pollution 
which is hard to cure, and which, in long-settled countries, causes laws to be 
enacted requiring all vaults for the reception of house and human waste to be 
made water-tight, so as to save the soil from its poisoning influence. 

This is the kind of poisoning which, in the Dark Ages, caused so much 
unrighteous persecution of the innocent. In those days, no care whatever 
was taken in the towns, high-walled, crowded, and unsewered, to protect the 
water supply from pollution — as a result, some terrible epidemic of fever would 
arise. Then the angry populace would, in their ignorance, cry out : "The 
Jews have poisoned the wells." The Avells were poisoned, no doubt, but the 
Jew was no more worthy of blame than were his accusers. Nevertheless, the 
Jews were not spared — they were robbed, imprisoned, executed. 

Drainage in the city is a comparatively easy problem when the city's sewers 
are laid in the' streets. In the country it is more difficult, and on this account 
the fewer fixtures or "modern improvements" there are in the house the bet- 
ter it will be. There should be no less care within the country house, where 
waste-pipes are put in, than in the city house. The material should be well 
selected, tightly joined, and properly ventilated. The water-closet should be 
remote from the house. Earth- closets are better than the ordinary vaults — 
house-waste from kitchen and laundry should be taken to a considerable dis- 
tance from the house, and far away from the well, and either deposited in a 
water-tight cesspool or conveyed away, by a system of subsoil drainage tiles, 
arranged so as to fertilize some unoccupied plot of ground. 

On Going- into the Country, 

To spend the summer in the country would be the choice of all city- dwellers, 
whenever their purses will permit of it. And there are not a few advantages 
in such a course ; the change of scene is good, the mountains and the seaside 
give a purer and cooler air — an air that invigorates and aids in restful sleep at 
night, so different from the midsummer atmosphere in hot cities. There are 
fewer excitements in the country ; we do not "live so fast," and there is full 
scope for healthful life and activit}' in the open air, with the green and blue 
of nature all about us, instead of the monotonous walls of towering houses. 

But this course, pleasant anil helpful to so many, is not without its danger. 



APPENDIX. 303 

Many who "go away" on vacation are brought home sick on account of fever 
or other sickness caused by defects and faults of drainage existing in these 
temporary summer homes. Scarcely a year goes by that one or more summer 
resorts have not gained the ill name of being the hotbeds of typhoid fever, 
dysentery, and the like. 

In view of this, how important it becomes that we exercise judgment, and 
seek skilled advice in the selection of our summering places. 

Again, there is another danger that must not be overlooked. Let us sup- 
pose that the summer vacation has passed by without accident ; that we return 
invigorated by the experience, and that the home in the city has been empty 
and closed during our absence ; what has happened that the air in the rooms 
newly reopened should be foul and stifling ? This has taken place ; the water 
that stands in the traps of house pipes, and shuts off gases from the sewer, 
when the rooms are in use and water is daily entering the different wash- 
basins, etc., has during our absence been evaporated. For weeks, perhaps, 
there has been no "water-seal" in the traps, and the ascent of sewer air has 
been going on continuously, so that not only is the air utterly unfit to live in, 
but all the curtains, carpets, and other absorbing materials have become 
saturated with the pollution thus allowed to enter. Let it be remembered 
that when a sink, etc. , is not in use, it is gradually losing the trap- water by 
the evaporation. 

What is the remedy, you will ask, for the condition of things caused by 
closing up the house, as above stated ? To this the reply is, that the house 
should from time to time be opened and aired, and water should be poured 
down each and every sanitary fixture, in sufficient quantity to renew the 
supply of water in the trap of each. 



GLOSSARY. 



Ab-do'men (Latin abdo, to conceal). The largest cavity of the body, contain- 
ing the liver, stomach, intestines, etc. ; the belly. 

Ab-sor/bents (L. ab and sorbeo, to suck up). The vessels which take part in 
the process of absorption. 

Ab-sorp'tion. The process of sucking up fluids by means of an animal mem- 
brane. 

Ac-com-mo-ba/tion of the Eye. The alteration in the shape of the crystalline 
lens, which accommodates or adjusts the eye for near and remote vision. 

Ac'id, Lactic (L. lac, milk). The acid ingredient of sour milk ; the gastric 
juice also contains it. 

Al-bu'men, or Albumin (L. albus, white). An animal substance resembling 
white of egg. 

Al-bu'mi-nose (from albumen). A soluble animal substance produced in the 
stomach by the digestion of the albuminoid substances. 

Al-bu'min-oid substances. A class of proximate principles resembling albu- 
men ; they may be derived from either the animal or vegetable kingdoms. 

Al/i-ment (L. alo, to nourish). That which affords nourishment; food. 

Al-i-ment'aby Ca-nal (from aliment). A long tube in which the food is 
digested, or prepared for reception into the system. 

An-.es-thet / ics (Greek, av, an, without, aiafirjoia, aisthesia, feeling). Those 
medicinal agents which prevent the feeling of pain, such as chloroform, 
laughing-gas, etc. 

An-i-mal'cule (L. animal' culum, a small animal). Applied to animals which 
can only be seen with the aid of the microscope. Animalculum (plural, 
animalcula) is used with the same meaning. 

A-or/ta (Gr. dopriouai, aorteomai, to be lifted up). The largest artery of the 
body, and main trunk of all the arteries. It arises from the left ventricle 
of the heart. The name was first applied to the two large branches of the 
trachea, which appear to be lifted up by the heart. 

A'que-ous Humor (L. aqua, water). A few drops of watery colorless fluid 
occupying the space between the cornea and crystalline lens. 

A-rach'noid Mem'brane (Gr. dpdxvrj, arachne, a cobweb, and ridoc, eidos, 



GLOSSARY. 305 

like). An extremely thin covering of the brain and spinal cord. It lies 

between the dura mater and the pia mater. 
Ar'bor Vi'TiE (L.). Literally, "the tree of life;" a name given to the pecu- 
liar appearance presented by a section of the cerebellum. 
Ar'ter-y (Gr. drip, aer, air, and rijpeiv, terein, to contain). A vessel by which 

blood is conveyed away from the heart. It was supposed by the ancients to 

contain air ; hence, the name. 
Ar-tic-u-la'tion (L. articulo, to form a joint). The more or less movable 

union of bones, etc. ; a joint. 
A-ryt'e-noid Cae/ti-la-ges (Gr. dpvraiva, arutaina, a pitcher). Two small 

cartilages of the larynx, resembling the mouth of a pitcher. 
As-sim-i-la'tion (L. ad, to, and similis, like). The conversion of food into 

living tissue. 
Au-di'tion (L. audio, to hear). The act of hearing sounds. 
Au'di-to-ry Nerve. One of the cranial nerves ; it is the special nerve of 

hearing. 
Att'ri-cle (L. auris, the ear). A cavity of the heart. 
Bar'i-tone (Gr. (Sapvg, barus, heavy, and tovoc., tonos, tone). A variety of 

male voice between the bass and tenor. 
Bel-la-don'na (It. beautiful lady). A vegetable narcotic poison. It has 

the property of enlarging the pupil, and thus increasing the brilliancy of the 

eye ; so called from its use by Italian ladies. 
Bi-ctjs'pid (L. bi, two, and cuspis, prominence). The name of the fourth and 

fifth teeth on each side of the jaw; possessing two prominences. 
Bile. The gall, or peculiar secretion of the liver ; a viscid, yellowish fluid, 

and very bitter to the taste. 
Bronch'i (Gr. fipbyx°G> brogchos, the windpipe). The two first divisions or 

branches of the trachea ; one enters each lung. 
Bronch'i-al Tubes. The smaller branches of the trachea within the sub- 
stance of the lungs, terminating in the air-cells. 
*Jronch-i'tis (from bronchia, and itis, a suffix signifying inflammation). An 

inflammation of the larger bronchial tubes; a "cold" affecting the 

lungs. 
Cal-ca're-ous (L. calx, lime). Containing lime. 
Ca-nai/ (L. ). In the body, any tube or passage. 
Ca-nine' (L. canis, a dog). Name given to the third tooth ok each side of 

the jaw; in the upper jaw it is also known as the eye-tooth, pointed like 

the tusks of a dog. 
Cap'il-la-ry (L. capiVlus, a^hair, capilla'ris, hair-like). The name of the 

extremely minute blood-vessels which connect the arteries with the veins. 
Car'bon Diox-ide (C0 3 ). Chemical name for carbonic acid gas. 
Car-bon'io A'cid. The gas which is present in the air expired from the 

lungs ; a waste product of the animal kingdom, and a food of the vegetable 

kingdom. 



306 GLOSSARY. 

Car'di-ac (Gr. KapSia, cardia, the heart). The cardiac orifice of the stomach 
is the upper one, and is near the heart ; hence its name. 

Cae-niv'o-eotjs (L. ca!ro, flesh, and vo'ro, to devour). Subsisting upon flesh. 

Ca-eot'id Ae-te-ey. The large artery of the neck, supplying the head and 
brain. 

Cae'ti-lage. A solid but flexible material, forming a part of the joints, air- 
passages, nostrils, etc.; gristle. 

Ca'se-ine (L. ca'seus, cheese). The albuminoid substance of milk, it forms 
the basis of cheese. 

Cee-e-bel'lum (diminutive for cer'ebrum, the brain). The little brain, situ- 
ated beneath the posterior third of the cerebrum. 

Cee'e-betjm (L.). The brain proper, occupying the entire upper portion of 
the skull. It is nearly divided into two equal parts, called " hemispheres," 
by a cleft extending from before backward. 

Cho'eoid (Gr. xbpwv, chorion, a membrane or covering). The middle tunic 
or coat of the eyeball. 

Chyle (Gr. xvTidc, chulos, juice). The milk-like fluid formed by the digestion 
of fatty articles of food in the intestines. 

Chyme (Gr. x v ^> chumos, juice). The pulpy liquid formed by digestion 
within the stomach. 

Cil/i-a (pi. of cil'i-um, an eyelash). Minute, vibratile, hair-like processes 
found upon the cells of the air-passages, and other parts that are habitually 
moist. 

Cie-cu-la'tion (L. cir* cuius, a ring). The circuit, or course of the blood 
through the blood-vessels of the body, from the heart to the arteries, through 
the capillaries into the veins, and from the veins back to the heart. 

Co-ag-u-la'tion (L. coag'ulo, to curdle). Applied to the process by which 
the blood clots or solidifies. 

Coch'le-a (L. coch'lea, a snail-shell). The spiral cavity of the internal ear. 

Conch' A (Gr. kovxv, (koncTie, a mussel-shell). The external shell-shaped por- 
tion of the external ear. 

Con-junc-ti' va (L. con and jun'go, to join together. A thin layer of mucous 
membrane which lines the eyelids and covers the front of the eyeball; 
thus joining the latter to the lids. 

Con-teac-tii/i-ty {L. con and tra'Jw, to draw together). The property 
of muscle which enables it to contract, or draw its extremities closer to- 
gether. 

Con-vo-lu'tions (L. con and vol'vo, to roll together). The tortuous foldings 
of the external surface of the brain. 

Con-vul'sion (L. convel'lo, to pull together). A more or less violent agita- 
tion of the limbs or body. 

Cor'ne-a (L. cor'nu, a horn). The transparent, horn-like substance which 
covers the anterior fifth of the eyeball. 

Coe'pus-cles, Blood (L. dim. of cor' pus, a body). The small bi-concave disks 



GLOSSARY. 307 

which give to the blood its red color; the white corpuscles are globular and 

larger. 
Cos-met'ic (Gr. Koafj.eo), kosmeo, to adorn). Beautifying ; applied to articles 

which are supposed to increase the beauty of the skin, etc. 
Cra'ni-al (L. era' nium, the skull). Pertaining to the skulL The nerves 

which arise from the brain are called cranial nerves. 
Cri'coid (Gr. KpUoc, Icri'kos, a ring). A cartilage of the larynx resembling 

a seal-ring in shape. 
Crys'tal-line Lens (L. crystal'lum, a crystal). One of the so-called humors 

of the eye ; a double convex body situated in the front part of the eyeball. 
Cu'ti-cle (L. dim. of cu'tis, the skin). The scarf-skin ; also called the 

epidermis. 
Cu'tis (L. , skin or hide). The true skin, lying beneath the cuticle ; also 

called the dermis. 
De-cus-sa'tion (L. decus'sis, the Roman numeral ten, X). A reciprocal cross- 
ing of fibres from side to side. 
Di'a-phragm (Gr. diacppdoco, diaphrasso, to divide by a partition). A large, 

thin muscle which separates the cavity of the chest from the abdomen ; a 

muscle of respiration. 
Dif-ftjs'ion of Gases. The power of gases to become intimately mingled, 

without reference to the force of gravity. 
Duct (L. du'co, to lead). A narrow tube ; the thoracic duct is the main trunk 

of the absorbent vessels. 
Du-o-de'num (L. duode'ni, twelve). The first division of the small intestines, 

about twelve fingers-breadth long. 
Du'ra Ma'ter (L. ). Literally, the hard mother ; the tough membrane which 

envelops the brain. 
Dys-pep'si-a (Gr. Svc, dus, difficult, and ttetttcj, pepto, to digest). Difficult 01 

painful digestion ; a disordered condition of the stomach. 
E-mul'sion (L. emul'geo, to milk). Oil in a finely divided state suspended 

in water. 
En-am'el (Fr. email). The dense material which covers the crown of the tooth. 
Endocardium (Gr. ev6o, endo, within, and icupSia, kardia, the heart. The 

lining membrane of the heart. 
En'er-gy, Specific, of a Nerve. When a nerve of special sense is excited, 

whatever be the cause, the sensation experienced is that peculiar to 

the nerve ; this is said to be the law of the specific energy of the nerves. 
Ep-i-glot'tis (Gr. eni, epi, upon, and yX&TTig, glottis, the entrance to the 

windpipe). A leaf-shaped piece of cartilage which covers the top of the 

larynx during the act of swallowing. 
Ex-cre'tion (L. excer'no, to separate). The separation from the blood of the 

waste particles of the body ; also the materials excreted. 
Ex-pi-ra'tion ( L. expi'ro, to breathe out). The act of forcing air out of the 

lungs. 



308 GLOSSARY. 

Ex-ten'sion (L. ex, out, and ten'do, to stretch). The act of restoring a limb, 
etc. , to its natural position after it has been flexed, or bent ; the opposite of 
Flexion. 

Fe-xes'tra (L. ). Literally, a window ; the opening between the middle and 
internal ear. 

Fi'brixe (L. fi'bra, a fibre). An albuminoid substance found in the blood ; in 
coagulating it assumes a fibrous form. % 

Flex'iox (L. fiecto, to bend). The act of bending a limb, etc. 

Fol'li-cle (L. dim. of fol'lis, a bag). A little pouch or depression in a mem- 
brane ; it has generally a secretory function. 

Fux'gous Growths (L. fun'gus, a mushroom). A low grade of vegetable life. 

Gax'gli-ox (Gr. yavyXtov, ganglion, a knot). A knot-like swelling in the 
course of a nerve ; a smaller nerve-centre. 

Gas'tric (Gr. yaarrip, gaster, stomach). Pertaining to the stomach. 

Glaxd (L. glans, an acorn). An organ consisting of follicles and ducts, with 
numerous blood-vessels interwoven ; it separates some particular fluid from 
the blood. 

Glos'so-phar-yx-ge'al Xerve (Gr. yluoca, glossa, the tongue, and Qapiryg, 
pharugx,th.e throat). The nerve of taste supplying the posterior third of the 
tongue ; it also supplies the throat. 

Glu'tex (L. ). Literally, glue ; the glutinous albuminoid ingredient of wheat 

Grax'ele (L. dim. of gra'num, a grain). A little grain ; a microscopic object 

Gus-ta'tiox (L. gusto, to taste). The sense of taste. 

Gus'ta-to-ry Nerve. The nerve of taste supplying the front part of the 
tongue, a branch of the "fifth" pair. 

Hem'or-rhage (Gr. uifia, hai'Tna, blood, and p'rjyvvfii, regnumi, to burst). 
Bleeding, or the loss of blood. 

Hem-i-ple'gia (Gr. #///cn^, hemisus, half, and tz/.tjgou, plesso, to strike). 
Paralysis, or loss of power, affecting one side of the body. 

Hem'i-spheres (Gr. cpalpa, sphaira, a sphere). Half a sphere, the lateral 
halves of the cerebrum, or brain proper. 

He-pat / ic (Gr. ij-Kap, hepar, the liver). Pertaining to the liver. 

Her-biv'o-rous (L. her'ba, an herb, and vo'ro, to devour). Applied to 
animals that subsist upon vegetable food. 

Hu'mor (L. ). Moisture : the humors are transparent contents of the eyeball. 

Hy-dro-pho'bi-a (Gr. vdop, hudor, water, and Qodzu, phobeo, to fear). A dis- 
ease caused by the bite of a rabid dog or other animal. In a person affected 
with it, convulsions are occasioned by the sight of a glittering object, like 
water, by the sound of running water, and by almost any external impres- 
sion. 

Hy'gi-exe (Gr. vyhia, hugieia, health). The art of preserving health and 
preventing disease. 

Hy'pero'pi-a. Abbreviated from Hy'per-met-ro'pi-a (Gr. virip, huper, be- 
yond, fifrpov, metron, the measure, and ify, ops, the eye). A defect of vision 



GLOSSARY. 309 

dependent upon a too short eyeball ; so called because the rays of light are 

brought to a focus at a point behind the retina ; the true "far sight." 
In-ci'sor (L. inci'do, to cut). Applied to the four front teeth of both jaws, 

which have sharp cutting edges. 
In'cus (L. ). An anvil ; the name of one of the bones of the middle ear. 
In-sal-i-va'tton (L. in, and sali'va, the fluid of the mouth). The mingling 

of the saliva with the food during the act of chewing. 
In-spi-ra'tion (L. in, and spi'ro, to breathe). The act of drawing in the 

breath. 
In-teg'u-ment (L. in, and te'go, to cover). The skin, or outer covering of the 

body. 
In-tes'tine (L. in'tus, within). The part of the alimentary canal which is 

continuous with the lower end of the stomach ; also called the intestines, or 

the bowels. 
I'ris (L. i'ris, the rainbow). The thin muscular ring which lies between the 

cornea and crystalline lens, and which gives the eye its brown, blue, or 

other color. 
Jtj'gu-lar (L. ju'gulum, the throat). The name of the large veins which run 

along the front of the neck. 
Lab' y-rinth (Gr. la(3vpivdog, laburin'thos, a building with many winding pas- 
sages). The very tortuous cavity of the inner ear, comprising the vestibule, 

semicircular canals, and the cochlea. 
Lach'ry-mal Apparatus (L. lach'ryma, a tear). The organs for forming and 

conveying away the tears. 
Lac'te-als (L. lac, lac'tis, milk). The absorbent vessels of the small intes- 
tines ; during digestion they are filled with chyle, which has a milky appear- 
ance. 
La-ryn/go-scope (Gr. lapvy£, larunx, the larynx, and okottso, skopeo, to look 

at). The instrument by which the larynx may be examined in the living 

subject. 
Lar'ynx (Gr.). The cartilaginous tube situated at the top of the windpipe, 

or trachea ; the organ of the voice. 
Lens (L. ) Literally, a lentil ; a piece of transparent glass or other substance 

so shaped as either to converge or disperse the rays of light. 
Lig'a-ment (L. li'go, to bind). A strong, fibrous material binding bones or 

other solid parts together; it is especially necessary to give strength to 

joints. 
Lig'a-titre. A thread of silk or other material used in tying around an 

artery. 
Lymph (L. lywJpha, spring-water). The colorless, watery fluid conveyed by 

the lymphatic vessels. 
Lym-phat'ic Vessels. A system of absorbent vessels. 
Mal'le-us (L. ). Literally, the mallet ; one of the small bones of the middle 



310 GLOSSARY. 

Mar' row. The soft, fatty substance contained in the central cavities of the 
bones : the spinal marrow,, however, is composed of nervous tissue. 

Mas-ti-ca'tion (L. mas'tico, to chew). The act of cutting and grinding the 
food to pieces by means of the teeth. 

Me-dtti/la Ob-lon-ga'ta. The "oblong marrow," or nervous cord, which is 
continuous with the spinal cord within the skulL 

Mem-bra' na Tym'pan-i (L.). Literally, the membrane of the drum ; a deli- 
cate partition separating the outer from the middle ear ; it is sometimes in- 
correctly called the drum of the ear. 

Mem'brake. A thin layer of tissue serving to cover some part of the body. 

Mi'cro-scope (Gr. [w<p6c, mikros, small, and okotzeu, skopeo, to look at). An 
optical instrument which assists in the examination of minute objects. 

Mo'lar (L. mo' la, a mill). The name applied to the three back teeth of each 
side of the jaw ; the grinders, or mill-like teeth. 

Mo'tor (L. mo'veo, Trio' turn, to more). Causing motion ; the name of those 
nerves which conduct to the muscles the stimulus which causes them to 
contract. 

Mu'cous Mem'brane. The thin layer of tissue which covers those internal 
cavities or passages which communicate with the external air. 

Mtr'cus. The glairy fluid which is secreted by mucous membranes, and which 
serves to keep them in a moist condition. 

My-o'pi-a (Gr. (ivo, muo, to contract, and uip, ops, the eye). A defect ©f 
vision dependent upon an eyeball that is too long, rendering distant objects 
indistinct ; near sight. 

Na'sal (L. na'sus, the nose). Pertaining to the nose ; the nasal cavities 
contain the distribution of the special nerve of smell. 

Nerve (Gr. vevpov, neuron, a cord or string). A glistening, white cord of 
cylindrical shape, connecting the brain or spinal cord with some other organ 
of the body. 

Nerve Cell. A minute, round and ashen-gray cell found in the brain and 
other nervous centres. 

Nerve Fi'bre. An exceedingly slender thread of nervous tissue found in the 
various nervous organs, but especially in the nerves ; it is of a white color. 

Nu-TRi' tiois* (L. nu'trio, to nourish). The processes by which the nourish- 
ment of the body is accomplished. 

(E-soph'a-gus (Gr.). Literally, that which carries food; the tube leading 
from the throat to the stomach ; the gullet. 

0-le-ag'i-nous (L. o'leum, oil). Of the nature of oil: applied to an impor- 
tant group of food principles — the fats. 

Ol-fac'to-ry (L. olfa'cio, to smell). Pertaining to the sense of smelL 

Oph-thal' mo-scope (Gr. d<pdalfj.6c, ophthalmos, the eye, and gkotteu, skopeo, 
to look at). An instrument devised for examining the interior of the globe 
of the eye. 

Op'tic (Gr. opdu, 5ilfOftcu,fut, opsomai, to see). Pertaining to the sense of sight 



GLOSSARY. 311 

Orbtt (L. or' bis, the socket). The bony socket or cavity in which the eye* 
ban is situated. 

Os'mose (Gr. uofxoe, osmos, a thrusting or impulsion). The process by whici 
liquids are impelled through a moist membrane. 

Os'se-ous (L. os, a bone). Consisting of, or resembling bone. 

Pat/ ate (L. pala'tum, (the palate). The roof of the mouth, consisting of the 
hard and soft palate. 

Pal'mar. Relating to the palm of the hand. 

Pan'cre-as (Gr. izav, pan, all, and upeac, kreas, flesh). A long, flat gland 
situated near the stomach; in the lower animals the analogous organ is 
called the sweet-bread. 

Pa-pii/l^e (L. papil'la). The minute prominences in which terminate the 
ultimate fibres of the nerves of touch and taste. 

Pa-rai/y-sis. A disease of the nervous system marked by the loss of sensa- 
tion, or voluntary motion, or both ; palsy. 

Par-a-ple'gi-a (Gr. napaTrlrjaau, paraplesso, to strike amiss). A form of pa- 
ralysis affecting the lower half of the body. 

Pa-tel'la (L. dim. of pat'ina,, a pan). The knee-pan ; a small bone. 

Pel' vis (L. ). Literally a basin ; the bony cavity at the lower part of the trunk. 

Pep'sin (Gr. 7rtTTTG),pep£o, to digest). The organic principle of the gastric juice. 

Per-i-CAr'di-UM (Gr. Tzepl, peri, and Kapdia, kardia, the heart). A porous 
^^ membrane enclosing the heart, and secreting a lubricating fluid. 

Per-i-stal'tic Move'ments (Gr. ■KepLcre'klu, peristello, to contract). The 
slow, wave-like movements of the stomach and intestines. 

Per-i-to-ne'um (Gr. ■Kepirelvu, perileino, to stretch around). The invest- 
ing membrane of the stomach, intestines, and other abdominal organs. 

Per-spi-ra'tion (L. perspi'ro, to breathe through). The sweat, or watery ex- 
halation of the skin ; when visible, it is called sensible perspiration, when 
invisible, it is called insensible perspiration. 

Pe'trous (Gr. nerpa, petra, a rock). The name of the hard portion of the 
temporal bone, in which is situated the drum of the ear and labyrinth. 

Phar'ynx (Gr. <pdpvy^, pharugx, the throat). The cavity between the back 
of the mouth and gullet. 

Phys-i-oi/o-gy (Gr. <j>vct,(;, phusis, nature, and 2-oyoc, logos, a discourse). The 
science of the functions of living, organized beings. 

Pi' A Ma'ter (L. ). Literally, the tender mother ; the innermost of the three 
coverings of the brain. It is thin and delicate ; hence the name. 

Pleu'ra (Gr. TT^evpd, a rib). A membrane covering the lung and lining the 
chest. There is one for each lung. 

Pleu'ri-sy. An inflammation affecting the pleura. 

Pneu-mo-gas'tric (Gr. nvevjuov, pneumon, the lungs, and yaorjip, gaster, the 
stomach). The name of a nerve distributed to the lungs and stomach ; it ia 
the principal nerve of respiration. 

PNED-MO'NIA(Gr.). 



312 GLOSSARY. 

Pees-by-o'pi-a (Gr. 7rpeo(3vc, presbus, old, and utp, ops, the eye). A defect 

of the accommodation of the eye, caused by the hardening of the crystalline 

lens ; the " far-sight " of adults and aged persons. 
Peoc'ess (L. proce'do, processus, to proceed, to go forth). Any projection 

from a surface. Also, a method of performance ; a procedure. 
Pty'a-lix (Gr. tttvclaov, ptualon, saliva). The peculiar organic ingredient ot 

the saliva. 
Pui/mo-na-by (L. pul'mo, pulmo'nis, the lungs). Pertaining to the lungs. 
Pulse (L. pd'lo, pul'sum, to beat). The striking of an artery against the 

finger, occasioned by the contraction of the heart, commonly felt at the wrist. 
Pu'pil (L. pupil'la). The central, round opening in the iris, through which 

light passes into the depths of the eye. 
Py-lo'eus (L. TTvhupoc, puloros, a gate-keeper). The lower opening of the 

stomach, at the beginning of the small intestine. 
Re'flex Action". An involuntary action of the nervous system, by which an 

external impression conducted by a sensory nerve is reflected, or converted 

into a motor impulse. 
Res-pi-ea'tion (L. res'piro, to breathe frequently). The function of breath- 
ing, comprising two acts: inspiration, or breathing in, and expiration, or 

breathing out. 
Ret'i-na (L. re'te, a net). The innermost of the three tunics or coats of the 

eyeball, being an expansion of the optic nerve. 
Sac'cha-eixe (L. sadcharum, sugar). Of the nature of sugar; applied to the 

important group of food substances which embraces the different varieties 

of sugar, starch, and gum. 
Sa-li'va (L. ). The moisture or fluids of the mouth, secreted by the salivary 

glands, etc. 
Scle-eot'ic (Gr. ovc/l^pof, shleros, hard). The tough, fibrous outer tunic of 

the eyeball 
Se-ba'ceous (L. se'bum, fat). Resembling fat ; the name of the oily secretion 

by which the skin is kept flexible and soft. 
Se-cee'tion (L. secer'no, secre'tum, to separate). The process of separating 

from the blood some essential important fluid ; which fluid is also called a 

secretion. 
Sem-i-cie'cu-lae Canals. A portion of the internal ear. 
Sex-sa'tion. The perception of an external impression by the nervous 

system ; a function of the brain. 
Sen-si-bil'i-ty, Geneeal. The power possessed by nearly all parts of the 

human body of recognizing the presence of foreign objects that come in con- 
tact with them. 
Se'eum (L. ). The watery constituent of the blood, which separates from the 

clot during the process of coagulation. 
Skel'e-ton (Gr.). The bony framework of an animal, the different parts of 

which are maintained in their proper relative positions. 



GLOSSARY. 313 

Spec'tro-scope (from spec'trum and gkotteo), scopeo, to examine the spectrum). 
An instrument employed in the examination of the spectrum of the sun or 
any other luminous body. 

Sphyg' mo-graph (Gr. a^vyuog, sphugmos, the pulse, and ypuipo, grapho, to 
write). An ingenious instrument by means of which the pulse is delineated 
upon paper. 

Sta'pes (L. ). Literally, a stirrup ; one of the small bones of the tympanum, 
or middle ear, resembling somewhat a stirrup in shape. 

3ym-pa-thet'ic System of Nerves. A double chain of nervous ganglia, 
connected together by numerous small turves, situated chiefly in front of 
and on each side of the spinal column. 

Syn-o'vi-a (Gr. ovv, sun, and o)6v, oon, egg, resembling an egg). The lubri- 
cating fluid of joints, so called because it resembles the white of egg. 

Sys'to-le (Gr. uvaTelTiu, sustello, to contract). The contraction of the heart, 
by which the blood is expelled from that organ. 

Tac-tile (L. tac'tus, touch). Relating to the sense of touch. 

Tem'po-ral (L. tew! pus, time, and tem'pora, the temples). Pertaining to the 
temples ; the name of an artery ; so called, because the hair begins to turn 
white with age in that portion of the scalp. 

Ten'don (L. ten' do, to stretch). The white, fibrous cord or band by which 
a muscle is attached to a bone ; a sinew. 

Tet'a-nus (Gr. relvo, teino, to stretch). A disease marked by persistent con- 
tractions of all or some of the voluntary muscles ; those of the jaw are some- 
times solely affected ; the disorder is then termed locked-jaw. 

Tho'rax (Gr. -&upa^, thorax, a breast-plate). The upper cavity of the trunk 
of the body, containing the lungs, heart, etc. ; the chest. 

Thy'roid (Gr. ■dvpeog, thureos, a shield). The largest of the cartilages of the 
larynx ; its angular projection in the front of the neck is called "Adam's 
apple. " 

Tra'che-a (Gr. rpajuc, trachus, rough). The windpipe, or the largest of the 
air-passages ; composed in part of cartilaginous rings, which render its sur- 
face rough and uneven. 

Trans-fu'sion (L. transfun'do, to pour from one vessel to another). The 
operation of injecting blood taken from one person into the veins of 
another ; other fluids than blood are sometimes used. 

f rich-i'na Spi-ra'lis (L. ). A minute species of parasite or worm, which in- 
fests the flesh of the hog, and which may be introduced into the human 
system by eating pork not thoroughly cooked. 

Tym'pa-num (Gr. rv/niravov, tumpanon, a drum). The cavity of the middle 
ear, resembling a drum in being closed by two membranes, and in having 
communication with the atmosphere. 

U're-a (Gr.). A substance secreted from the blood by the kidneys. 

U'vu-La (L. uva, a grape;. The small pendulous body attached to the back 
part of the palate. 



314 GLOSSARY. 

Vas'cu-lar (L. vadculum, a little vessel). Pertaining to, or containing blood- 
vessels. 

Ve'nous (L. ve'na, a vein). Pertaining to, or contained within a vein. 

Ven-ti-la'tion. The introduction of fresh air into a room or building in 
such a manner as to keep the air within it in a pure condition. 

Ven-tril'o-quism (L. ven'ter, the belly, and lo'quor, to speak). A modifica- 
tion of natural speech by which the voice is made to appear to come from a 
distance. The ancients supposed that the voice was formed in the belly : 
hence the name. 

V en'tri-cles of the heart. The two largest cavities of the heart, situated at 
its apex or point. 

Yer'te-bral Column (L. ver'te-bra, a joint). The back-bone, consisting of 
twenty-six separate bones, called vertebras, firmly jointed together; also 
called the spinal column and spine. 

Ves'ti-bule. A portion of the internal ear, communicating with the semi- 
circular canals and the cochlea ; so called from its fancied resemblance to 
the vestibule or porch of a house. 

Vil'li (L. vil'lus, the nap of cloth). Minute thread-like projections found 
upon the internal surface of the small intestine, giving it a velvety appear- 
ance. 

Vit're-ous (L. vi'trum, glass). Having the appearance of glass, applied to 
the humor occupying the largest part of the cavity of the eyeball. 

Viv-i-sec'tion (L. vi'vus, alive, and se'co, to cut). The practice of operating 
upon living animals, for the purpose of studying some physiological process. 

Vocal Cords. Two elastic bands or ridges situated in the larynx ; they are 
the essentia] parts of the organs of the voice. 



INDEX. 



PAGE 

Absorbent vessels 121 

Absorption 119 

by blood vessels 119 

by the lacteals • 120 

of the food 119 

Accommodation, function of 256 

Achilles, tendon of 35 

Adam's apple 273 

Ague-cake 1*5 

Air, atmospheric 161 

Changes in, in respiration 16 i 

Composition of 162 

Dust in the 168 

Effects of impure 169 

Impurities in 166 

Provision for purifying 172 

Renovation by ventilation 174 

Air-cells of the lungs 156 

Air-passages 155 

Albinos 51 

Albumen 72 

of the blood 130 

Albuminoid substances 71 

Varieties of 72 

Properties of 72 

Albuminose 117 

Alcohol, as a fat-producer 151 

as a food 98 

a poison to the intellect 211 

Cold-promoting, properties of 99 

Effects of , on digestion 125 

Effects of, on the brain 210 

Effects of , on the heart 150 

Effects of, on the kidneys 126 

Effects of, on the liver 126 

Effects of, on the mind 211 

for thirst 99 

History of 97 

Hostility of, to life 101 

in the army 99 

impairs the will. 211 

Kinds of 98 

Properties of 98 

Proper use of 101 

Trembling due to 210 

Alimentary canal 105 

Animal functions 184 

Animal heat 175 

How produced 175 

regulated by perspiration 178 

Animals, relative strength of 35 

Apoplexy 203 

Aqueous humor — 252 

Arachnoid membrane 183 

Arbor vitae 187 

Arterial blood 135-165 

differs from venous 165 

Arteries 143 

Arrangement of 143 

Carotid 144 

Pulsation of 143 

Radial 144 



PAGE 

Arteries, Temporal 144 

Arytenoid cartilage 273 

Asphyxia 293 

Assimilation 104, 148 

Audition 259 

Auditory canal 261 

nerve ■ 265 

Auricles of the heart 137 



Back-bone 22 

Bathing 54 

Importance of 54 

Time and manner of. 57 

Baths 56 

Different kinds of 56 

Belladonna 249 

Use of, as a cosmetic 249 

Bile 118 

Secretion of, in the liver 118 

Accumulation of, in the gall-bladder. 119 

Uses of 119 

Biliary duct 119 

Bladder 119 

Gall 124 

Bleeding, how stopped 149 

Blind-spot 250 

Blood..... 129 

Arterial 135 

Change of color 135 

Circulation of 136-164 

Coagulation of 132 

Composition of .... 130 

corpuscles 130 

fluid 133 

Microscopic appearance of 130 

Respiratory changes in 164 

Usesofthe 133 

Venous 135-165 

Blood-vessels 143,146 

Absorption by ..119,120 

Injuries to the 149 

Body, renovation of the 85 

Bones 15 

Form and composition of 16 

Growth of 24 

Microscopic structure of 17 

Repairof 24 

Structure of. 17 

Uses of 15 

Brain 183 

Anatomical structure of. 183 

Function of the 204, 205 

Injuries of the 206 

Membranes of the 183 

Reflex action of the 208 

Bread. 92 

Bronchial tubes 155 

Bronchitis 158 



Canals, Semicircular.. 265 

Capillary blood-vessels 146 

Circulation in the 146 



316 



INDEX. 



PAGE 

Carbonic acid 162 

exhaled from the lungs . . . 162 

in the air 168 

Ketention of, in the blood 166 

Cartilage 21 

Arytenoid 273 

Cricoid 273 

Thyroid 273 

Caseine 73 

Cataract ... 252 

(Jells, Nerve... 182, 192 

Ciliated 158 

Cerebellum 181 

Function of the 204 

Cerebrospinal nervous system 185 

Cerebrum 184 

Function of the 204 

Cheese 73 

Chest, Framework of 19 

Contents of the 19 

Chloral hydrate 217 

Effects of 217 

Chloroform, Use of 217 

Chocolate 97 

Chorea 202 

Choroid coat of the eye 247 

Chyle 119 

Chyme 119 

Cigarette smoking 216 

Cilia 15S 

Circulation 136 

in the frog's foot 146, 

of the blood 

Rapidity of 

through the heart 

through the luugs 

Clothing 

Coagulation of milk 

of the blood 

Cochlea 

Coffee 

Effects of 

Collar-bone 

Color-blindness 

Column. Spinal 

Combustion, Spontaneous 

Complexion 

Concha of the ear 

Conjunctiva — 

Contraction of heart 

Contraction of muscles 

Convulsions 

Cooking 

Cords, Vocal 156, 

Cornea 

Corpuscles, Blood 

Cosmetics 



Country, On going into the 
Cranial Ganglia 

Functions of . 

Cranial nerves 

Cricoid cartilage 

Crystalline lens 

Uses of 

Cuticle 

Function of. 

Cutis 



147 
136 

143 
139 
154 

60 

72 
132 
205 

97 

97 

19 
252 

22 
179 

52 
261 
243 
138 

34 
207 

89 
274 
247 
130 

63 
302 
183 
204 
188 
273 
252 
253 

48 
227 

48 



Decussation of motor and sensory fibres 

of spinal cord 197 



PAGE 

Dentition of infancy 106 

Diaphragm, Movements of the, in 

respiration 159 

Diastole of the heait 138 

Diet. Mixed 85, 109 

Necessity for changing 87 

Necessity of a regulated 7? 

The best 78 

Digestion 104 

Circumstances affecting 121 

Gastric ,..116 

Intestinal 118 

Nature of 105 

Organs of 105-113 

Disinfection 295 

Drainage 300-302 

Drain diseases 300 

Drowning 293 

Duct, Biliary 119 

Nasal 245 

Pancreatic 118 

Thoracic 121 

Dura Mater 183 

E 

Ear 260 

External 260 

Internal 265 

Middle 262 

Foreign bodies in the 268 

Drum of the 262 

Bones of the 263 

Ear-sand 265 

Ear-stones 265 

Ear-wax 261 

Eggs 88 

Composition of 88 

Emulsion of fats, in digestion 119 

Endocardium 136 

Epiglottis 156 

Uses of 156 

Eustachian tube 263 

Exercise 36 

Different modes of 39 

Effects of 37 

Importance of 36 

Open-air 40 

Expiration , Movements of 159 

Extensor Muscles 32 

Eye 242 

Eyeball 246 

Eyelashes 244 

Eyelids 243 

P 

Fats, Emulsion of 73 

Source of, in food — 73 

Fenestra ovalis 266 

Fibres, Muscular 34 

" Nervous 182 

Fibrine in food 73 

of the blood 130 

Fish, as food 91 

Flexor muscles 32 

Food 65 

Animal 86 

Daily quantity of. 83 

Ingredients of 67-77 

Necessity for 81 

Source of 65 

Vegetable 91 



INDEX. 



317 



PAGE 

G 

Gall-bladder 119 

Ganglia, cranial, Functions of the 204 

Gases, Interchange of, in the lungs,... 164 

Gastric digestion 116 

Gastric juice 114 

Action of 115 

Daily quantity of 115 

General sensibility 221 

Glands, Perspiratory 53 

Salivary 110 

Sebaceous 52 

Glossary 304 

Glossopharyngeal nerve 232 

Gullet 114 

Gum 77 

as food 77 

Gustatory nerve 232 

Gymnastics 41 

for schools and colleges 41 

H 

Hair 50 

Uses of 51 

Hasheesh 217 

Health and Home 300 

Hearing, Sense of 258 

Protection of... 266 

Heart 136 

Cavities of the 137 

Circulation through the 139 

Frequency of action 139 

Movements of the 137 

Valves of the 139 

Heat, Animal 176 

Production of 176 

Regulation of ..177, 178 

Hemiplegia 198 

House, Location of 390 

Humor, Aqueous 252 

Crystalline 252 

Vitreous 252 

Hunger 82 

Seat of the sensation of 82 

Hydra 182 

Hydrophobia 202 

Hygiene 13 

Hyperopia 254 

I 
Incus.... 263 

Inorganic substances in food 67 

Insalivation 110 

Insensible perspiration 53 

Inspiration 159 

Intestinal juice 119 

Action of „ 119 

Intestines 118 

Complete digestion in the small 118 

Villi of the 120 

Iris 248 

Function of 248,249 

Iron 71 

Proportion in the blood 71 

Proportion in the food 71 

J 

Joints 19 

Varieties of 20 

Juice, gastric 114 

Intestinal 119 

Pancreatic 119 



Kidneys 125 

Kerosene 298 



Labyrinth 265 

Lachrymal canals 245 

gland 244 

Lacteals ... . 38 

Absorption by 38 

Lactic acid in gastric- juice 115 

Lactometer 88 

Large intestines 118 

Laryngoscope 275 

Larynx 156,273 

Production of the voice in the 273 

Lens, Crystalline 252 

Ligaments 19 

Light, Theory of 240,241 

Lime in the bones 16 

inthefood.. 70 

Importance of. 70 

Liver 118 

Secretion of the 118 

Locked jaw 202 

Long-sight 254 

Lungs 154 

Capacity of 160 

Structure of 155, 156 

Lymph 121 

Lymphatic vessels 121 

M 

Magendie, on pain 224 

Magnesia, compounds of, in food 71 

Malleus 263 

Marrow of the bones 17 

Mastication 105 

Importance of 112 

Meats 88 

The cooking and preservation of ... . 89 

Membrane of the tympanum 262 

Medulla oblongata 187 

Function of the 203 

Microscope .. 281 

Simple 283 

Compound 284 

The use of the 281 

Milk 87 

Composition of. 87 

Specific gravity of 87, 88 

Milk-teeth 106 

Morphine 216 

Mucous membrane of air passages. ... 157 

Muscles, Function of the 31 

Flexion and extension of 32 

Voluntary and involuntary 32 

Muscular contraction 34 

fibres 81 

sense 231 

Myopia 254 

N 

Nails BO 

Usesofthe 51 

Nasal cavities.. 235 

duct 245 

Narcotics, kinds of 216 

Property of 216 

and sleep 216 

and digestion 218 



318 



INDEX. 



PAGE 

Nerve, Auditory 265 

Glossopharyngeal ,.. 232 

Gustatory 232 

Olfactory 236 

Optic 240 

Sympathetic 191 

Nerve cells 182-191 

Nerve-fibres 182 

Nerves, Cranial 188 

Spinal 159 

Functions of the 194 

Sensory, functions of the 194 

Motor, functions of the 194' 

Sympathetic system of 190 

Nervous system 182 

Cerebro-spinal 183 

Nervous tissue, Properties of 192 

Nicotine 214 

Nose 235 

Nutrition, Processes of 104 

O 

(Esophagus 114 

Oil, Sources of, in food 73 

Old-sight 275 

Olfactory nerve 236 

Optic nerve 240 

Opiates, Effects of 216 

Opium, and its effects 216 

Orbicular bone 263 

Orbit of the eye . . . 242 

Organic substances as food 71-77 

Organs of circulation 136 

Digestion 104 

Eespiration 154 

Sight 242 

Voice 271 

Oxygen 162 

Amount of, consumed in respiration. 162 
Continually supplied by the atmo- 
sphere 173 

P 

Pain, Eelations of. to pleasure 224 

Sensation of 222 

Uses of. 223 

Pancreatic juice 119 

Uses of 120 

Pancreatin 119 

Paraplegia 196 

Parlor gymnasium 43 

Passages, Air ... 155 

Pelvis 19 

Pepsin 115 

Pericardium 136 

Peristaltic action of the stomach 116 

Peritoneum 118 

Perspiration, Daily amount of 53, 54 

Sensible and insensible 53 

Uses of 54,178 

Perspiratory glands 53 

Phvsical strength 36 

Culture 40 

Physiology 11 

Animal *..... 11 

Comparative 11 

Human 11 

Vegetable 11 

Pia mater 183 

Plasma of the blood 130 

Pleura 155 

Pleurisy 158 



PAGE 

Pneumo-gastric nerve 204 

Pneumonia 158 

Poisons and their antidotes 290 

Potash in the blood 71 

Potato 93 

Presbyopia 275 

Preservatior of the teeth 109 

Ptyalin 112 

Pulsation of the heart 141 

of the arteries 143 

Pulse 143 

formofthe 144 

writer 144 

Pylorus 114 

R 

Radial artery 144 

Eed corpuscles of the blood 130 

Reflex action of the spinal cord 198 

Requisites for 200 

Uses of 200 

Causing convulsions 202 

Objects of 203 

of the brain 208 

Rennet 73 

Respiration . 154 

Change of blood in 154-164 

Frequency of 159 

Movements of 159 

Object of 154 

Organs of 154 

Respiratory labor 166 

Rest, Necessity for 44 

Retina... 249 

Retinal light 250 

Ribs, Movements of, in respiration. ... 159 

S 

Saccharine substances 75 

Saliva 110 

Importance of 112 

Secretion of 110 

Salivary glands 110 

Salt, Common 68 

Importance of 69 

Scalds 297 

Scars from burns 298 

Sclerotic coat of the eyeball 247 

Sebaceous glands , ,. 52 

Secretion of. 53 

Semicircular canals 265 

Sensation of pain 222 

Relations of, to pleasure 224 

of temperature . 234 

of weight 231 

Modification of 221 

Production of ... 220 

Variety of 221 

Sense of hearing 258 

sight 240 

smell 235 

taste 233 

touch 228 

Sense. Muscular 231 

Thermal 230 

Senses. Special 220 

Sensibility, General 221 

Sewers, Danger from 301 

Short-sight 254 

Sick-room, Care of the 293 

Sight, Sense of 240 

Organ of 242 



INDEX. 



319 



PAGE 

Sinews 33 

Skeletonj 19 

Skin, Structure of 48 

Skull, and its uses 19 

Sleep, Necessity for 44 

Amount required 45 

Small iutestines 120 

Smell, Sense of. 235 

Nerve of. 236 

Uses of 237 

Smoking, Effects of 214 

Cigarette 216 

Soda in the food 71 

Sound, Production of 258 

Special senses 220 

Spectroscope 131 

Speech 271 

Eelation of, to the sense of hearing. 272 

Sphygmograph 144 

Spinal column 22 

Spinal cord 188 

Decussation of the. . 198 

Direction of fibres in 197 

Fnnctions of the 196 

Nerves of 189 

Reflex action of 198 

Spleen 125 

Spontaneous combustion 179 

Stapes 263 

Starch 76 

Its change into sugar 77 

Different kinds 76 

Effect of boiling 76 

Microscopic appearance 76 

Stimulating substances 77 

Stimulation .• 212 

Stomach 113 

Digestion 116 

Movements of 115 

Secretion of 115 

St. Vitus' dance 202 

Sugar, Varieties 75 

Sources of. 75 

Sun-bath 60 

Sympathetic system of nerves 190 

Synovia 21 

Systole of the heart 138 

T. 

Taste, Association of 234 

Education of. 235 

Organ of 232 

Sense of 233 

Tea, Effectof 97 

Tears 244 

Teeth, Temporary set of 106 

Permanent set of 106 

Bicuspid 107 

Canine 106 

Incisor 106 

Molar 106 

Arrangement of 107 

of different animals 108 

Preservation of 109 

Temperature of the body 179 

Extremes of. 179 

Sensations of 230 

Tendon of Achilles 34 

Tendons 33 

Tetanus 202 

Thermae 59 

Thermal sense 230 



PAGE 

Thirst 82 

Thoracic duct 121 

Thorax 19 

Thyroid cartilage 273 

Tissues, Intimate structure of the 282 

Human 288 

I of the lower animals 

ITobacco 214 

as a poison 214 

Effects on the young 215 

when in training 215 

Tongue 232 

Nerves of 233 

Sensibility of 233 

Touch, Delicacy of 229 

Organs of 227 

Sense of 223 

Trachea 155 

Transfusion 134 

Trap 300 

water 301 

Trichina spiralis 91 

Trunk 19 

Tympanum of the ear 262 

Membrane of 262 

U 

Urea 124 

Ureter 124 

V 

Valves of the heart 139 

of the veins 145 

Vapor, Animal, in breath 162 

Vegetable food 91 

Vegetative functions 181 

Veins, Valves of 145 

Venous blood 165 

Changes of, in respiration 162 

Ventilation 174 

by window 175 

Ventricles of the larynx 275 

of the heart 137 

Ventriloquism 279 

Vertebra? 22 

Vestibule of the internal ear 265 

Villi of the intestines 121 

Absorption by 121 

Vitalknot 204 

Vitreous humor 253 

Vocal cords 156,274 

Observation of, with laryngoscope... 275 

Voice 271 

Organ of 273 

Production of 276 

Varieties of 277 

W 

Waste-pipes 300 

Water 94 

Action of, on lead 95 

Chemically pure 94 

exhaled with the breath 162 

from springs and wells 94 

Proportion of, in the bloofi 67 

" of, in the tissues and 

fluids of the body 67 

Water-seal 301 

Walking, as a means of exercise. 39 

Well, care of the 801 

White corpuscles of the blood. 131 

Wisdom teeth 10? 






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